Fair Value Measurements - Schedule of Reconciliation of Debt Securities (Detail) - Debt Securities [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2016
Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning balance		$ 12,658	$ 12,658
Accrued interest income			640
Unrealized loss on debt securities	$ (3,000)	$ (800)	(3,860)
Ending balance	$ 9,438		$ 9,438