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		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Opening Balance, Liabilities	$ 38,709	$ 42,139	$ 42,159	$ 45,984
Total realized and unrealized (gains) losses included in Net income (loss), Liabilities	(772)	(1,940)	369	(3,422)
Unrealized (gains) losses included in Other comprehensive income (loss), Liabilities	(8)	295	(67)	(280)
Purchases/ Issuances, Liabilities			2,959
Sales/ Settlements, Liabilities	(4,382)	(1,632)	(9,709)	(7,534)
Closing Balance, Liabilities	35,107	42,152	35,107	42,152
Unrealized (gains) losses for the period included in Net income (loss) on Level 3 Assets/Liabilities Outstanding	(772)		369
Unrealized (gains) for the period included in Other comprehensive income (loss) on Level 3 Assets/Liabilities Outstanding	$ (8)		$ (67)
Unrealized (gains) losses for the period on Level 3 Assets/Liabilities Outstanding		$ (1,645)		$ (3,702)