Fair Value of Financial Assets and Liabilities - Changes in Level 3 Contingent Consideration Measured at Fair Value on Recurring Basis (Detail) - Accounts Payable Accrued and Other Liabilities [Member] - Contingent Consideration [Member] - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Opening Balance	$ 62,272	$ 77,693	$ 65,043	$ 56,299
Total realized and unrealized gains (losses) included in Net income(loss)	16,570	(307)	15,822	(1,772)
Unrealized gains (losses) included in Other comprehensive income (loss)	(14)	184	131	383
Issuances	5,631	1,031	7,042	25,250
Settlements	(1,366)	(2,554)	(6,151)	(6,645)
Closing Balance	49,981	76,293	49,981	76,293
Unrealized gains (losses) for Level 3 Assets / Liabilities Outstanding	$ (711)	$ (123)	$ (1,314)	$ (1,389)