Summary of Change in Reserves for Discounts and Allowances (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Accounts Notes And Loans Receivable [Line Items]
Beginning balance	$ 70,466	$ 50,970
Provision	81,611	49,739
Payments/credits	(66,624)	(44,648)
Ending balance	85,453	56,061
Chargebacks [Member]
Accounts Notes And Loans Receivable [Line Items]
Beginning balance	799	2,281
Provision	5,642	5,665
Payments/credits	(6,232)	(6,887)
Ending balance	209	1,059
Rebates [Member]
Accounts Notes And Loans Receivable [Line Items]
Beginning balance	60,506	41,771
Provision	50,361	33,221
Payments/credits	(43,293)	(26,992)
Ending balance	67,574	48,000
Prompt Pay [Member]
Accounts Notes And Loans Receivable [Line Items]
Beginning balance	2,798	1,949
Provision	6,192	4,005
Payments/credits	(5,639)	(3,533)
Ending balance	3,351	2,421
Other Accruals [Member]
Accounts Notes And Loans Receivable [Line Items]
Beginning balance	6,363	4,969
Provision	19,416	6,848
Payments/credits	(11,460)	(7,236)
Ending balance	$ 14,319	$ 4,581