Fair Value of Financial Assets and Liabilities - Changes in Level 3 Liabilities Measured at Fair Value on Recurring Basis (Detail) - Level 3 - Accounts Payable Accrued and Other Liabilities - Contingent Consideration [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 40,056	$ 38,709	$ 39,791	$ 42,159
Total realized and unrealized (gains) losses included in Net income (loss)	838	772	1,939	(369)
Unrealized (gains) losses included in Other comprehensive income (loss)¹	0	8	0	67
Purchases/ Issuances	0	0	0	2,959
Sales/ Settlements	(7,919)	(4,382)	(8,755)	(9,709)
Closing Balance	32,975	35,107	32,975	35,107
Net income (loss) on Level 3 Assets/ Liabilities Outstanding	838	772	1,939	(369)
Other comprehensive income (loss) on Level 3 Assets / Liabilities Outstanding	$ 0	$ 8	$ 0	$ 67