Fair Value of Financial Assets and Liabilities - Changes in Level 3 Liabilities Measured at Fair Value on Recurring Basis (Detail) - Level 3 [Member] - Accounts Payable Accrued and Other Liabilities [Member] - Contingent Consideration [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Opening Balance, Liabilities	$ 39,791	$ 42,159
Total realized and unrealized (gains) losses included in Net income (loss), Liabilities	1,102	(1,141)
Unrealized (gains) losses included in Other comprehensive income (loss), Liabilities		59
Purchases/ Issuances, Liabilities		2,959
Sales/ Settlements, Liabilities	(837)	(5,327)
Closing Balance, Liabilities	40,056	38,709
Unrealized (gains) losses for the period included in Net income (loss) on Level 3 Assets/Liabilities Outstanding	$ 1,102	(1,141)
Unrealized (gains) losses for the period included in Other comprehensive income (loss) on Level 3 Assets/Liabilities Outstanding		$ 59