Revenue - Schedule of Revenue by Payor Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue	$ 3,334,106	$ 2,601,229	$ 9,359,933	$ 7,325,249
Commercial Insurance
Disaggregation of Revenue [Line Items]
Revenue	869,600	661,000	2,371,600	1,818,700
Medicaid
Disaggregation of Revenue [Line Items]
Revenue	415,700	298,800	1,093,700	852,300
Medicare A
Disaggregation of Revenue [Line Items]
Revenue	270,000	256,200	797,500	726,200
Medicare B
Disaggregation of Revenue [Line Items]
Revenue	20,400	20,500	61,500	69,100
Medicare C
Disaggregation of Revenue [Line Items]
Revenue	621,800	442,100	1,732,300	1,205,200
Medicare D
Disaggregation of Revenue [Line Items]
Revenue	1,058,400	826,200	2,977,700	2,352,500
Private and Other
Disaggregation of Revenue [Line Items]
Revenue	78,200	96,400	325,600	301,200
Pharmacy Solutions
Disaggregation of Revenue [Line Items]
Revenue	2,967,000	2,265,700	8,289,200	6,357,200
Pharmacy Solutions \| Commercial Insurance
Disaggregation of Revenue [Line Items]
Revenue	818,300	619,100	2,234,800	1,693,700
Pharmacy Solutions \| Medicaid
Disaggregation of Revenue [Line Items]
Revenue	287,400	213,900	791,800	600,900
Pharmacy Solutions \| Medicare A
Disaggregation of Revenue [Line Items]
Revenue	143,000	141,900	422,300	399,000
Pharmacy Solutions \| Medicare B
Disaggregation of Revenue [Line Items]
Revenue	18,700	16,800	56,900	50,400
Pharmacy Solutions \| Medicare C
Disaggregation of Revenue [Line Items]
Revenue	593,000	406,100	1,636,300	1,120,900
Pharmacy Solutions \| Medicare D
Disaggregation of Revenue [Line Items]
Revenue	1,058,400	826,200	2,977,700	2,352,500
Pharmacy Solutions \| Private and Other
Disaggregation of Revenue [Line Items]
Revenue	48,200	41,700	169,400	139,800
Provider Services
Disaggregation of Revenue [Line Items]
Revenue	367,100	335,500	1,070,700	968,000
Provider Services \| Commercial Insurance
Disaggregation of Revenue [Line Items]
Revenue	51,300	41,900	136,800	125,000
Provider Services \| Medicaid
Disaggregation of Revenue [Line Items]
Revenue	128,300	84,900	301,900	251,400
Provider Services \| Medicare A
Disaggregation of Revenue [Line Items]
Revenue	127,000	114,300	375,200	327,200
Provider Services \| Medicare B
Disaggregation of Revenue [Line Items]
Revenue	1,700	3,700	4,600	18,700
Provider Services \| Medicare C
Disaggregation of Revenue [Line Items]
Revenue	28,800	36,000	96,000	84,300
Provider Services \| Private and Other
Disaggregation of Revenue [Line Items]
Revenue	$ 30,000	$ 54,700	$ 156,200	$ 161,400
Product Concentration Risk \| Revenue
Disaggregation of Revenue [Line Items]
% of Revenue	100.00%	100.00%	100.00%	100.00%
Product Concentration Risk \| Revenue \| Commercial Insurance
Disaggregation of Revenue [Line Items]
% of Revenue	26.00%	25.40%	25.40%	24.80%
Product Concentration Risk \| Revenue \| Medicaid
Disaggregation of Revenue [Line Items]
% of Revenue	12.40%	11.50%	11.70%	11.60%
Product Concentration Risk \| Revenue \| Medicare A
Disaggregation of Revenue [Line Items]
% of Revenue	8.10%	9.90%	8.50%	9.90%
Product Concentration Risk \| Revenue \| Medicare B
Disaggregation of Revenue [Line Items]
% of Revenue	0.70%	0.70%	0.60%	1.00%
Product Concentration Risk \| Revenue \| Medicare C
Disaggregation of Revenue [Line Items]
% of Revenue	18.70%	17.00%	18.50%	16.50%
Product Concentration Risk \| Revenue \| Medicare D
Disaggregation of Revenue [Line Items]
% of Revenue	31.70%	31.80%	31.80%	32.10%
Product Concentration Risk \| Revenue \| Private and Other
Disaggregation of Revenue [Line Items]
% of Revenue	2.40%	3.70%	3.50%	4.10%
Product Concentration Risk \| Revenue \| Pharmacy Solutions
Disaggregation of Revenue [Line Items]
% of Revenue	89.00%	87.10%	88.60%	86.80%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Commercial Insurance
Disaggregation of Revenue [Line Items]
% of Revenue	24.50%	23.80%	23.90%	23.10%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Medicaid
Disaggregation of Revenue [Line Items]
% of Revenue	8.60%	8.20%	8.50%	8.20%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Medicare A
Disaggregation of Revenue [Line Items]
% of Revenue	4.30%	5.50%	4.50%	5.40%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Medicare B
Disaggregation of Revenue [Line Items]
% of Revenue	0.60%	0.60%	0.60%	0.70%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Medicare C
Disaggregation of Revenue [Line Items]
% of Revenue	17.80%	15.60%	17.50%	15.30%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Medicare D
Disaggregation of Revenue [Line Items]
% of Revenue	31.70%	31.80%	31.80%	32.10%
Product Concentration Risk \| Revenue \| Pharmacy Solutions \| Private and Other
Disaggregation of Revenue [Line Items]
% of Revenue	1.50%	1.60%	1.80%	2.00%
Product Concentration Risk \| Revenue \| Provider Services
Disaggregation of Revenue [Line Items]
% of Revenue	11.00%	12.90%	11.40%	13.20%
Product Concentration Risk \| Revenue \| Provider Services \| Commercial Insurance
Disaggregation of Revenue [Line Items]
% of Revenue	1.50%	1.60%	1.50%	1.70%
Product Concentration Risk \| Revenue \| Provider Services \| Medicaid
Disaggregation of Revenue [Line Items]
% of Revenue	3.80%	3.30%	3.20%	3.40%
Product Concentration Risk \| Revenue \| Provider Services \| Medicare A
Disaggregation of Revenue [Line Items]
% of Revenue	3.80%	4.40%	4.00%	4.50%
Product Concentration Risk \| Revenue \| Provider Services \| Medicare B
Disaggregation of Revenue [Line Items]
% of Revenue	0.10%	0.10%	0.00%	0.30%
Product Concentration Risk \| Revenue \| Provider Services \| Medicare C
Disaggregation of Revenue [Line Items]
% of Revenue	0.90%	1.40%	1.00%	1.20%
Product Concentration Risk \| Revenue \| Provider Services \| Private and Other
Disaggregation of Revenue [Line Items]
% of Revenue	0.90%	2.10%	1.70%	2.10%