Fair Value Measurements - Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	$ 77,929	$ 77,478
Specific valuation allowance allocations	(8,102)	$ (4,378)
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	0		$ 163
Specific valuation allowance allocations	0		(71)
Loans receivable, fair value disclosure	0		92
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	11,183		2,039
Specific valuation allowance allocations	(2,944)		(437)
Loans receivable, fair value disclosure	$ 8,239		$ 1,602