Fair Value Disclosures - Schedule of Roll-forward of Fair Value of Level 3 Instruments (Detail) - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Balance at beginning of period	$ 111,013	$ 106,000
Amounts acquired or issued	0	0
Net change in fair value	1,786	6,799
Settlements	0	0
Transfers in and/or out of Level 3	0	0
Balance at end of period	$ 112,799	$ 112,799