Fair Value Measurements - Impaired Loans Remeasured and Reported at Fair Value of Underlying Collateral (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	$ 171,820	$ 77,478
Specific valuation allowance allocations	(30,302)	$ (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		$ 197
Specific valuation allowance allocations	0		(71)
Loans receivable, fair value disclosure	0		126
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of impaired loans before allocations	45,751		1,107
Specific valuation allowance allocations	(11,144)		209
Loans receivable, fair value disclosure	$ 34,607		$ 1,316