Derivative Instruments and Hedging Activities - Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Interest Rate Caps and Swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	78,628	50,752
Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Assets	14,990	8,942
Other Liabilities	33,770	26,129
Notional Amount	1,040,106	1,040,209
Derivatives designated as hedging instruments: | Cash Flow Hedge | Interest Rate Caps and Swaps
Derivative [Line Items]
Other Assets	536	1,284
Other Liabilities	32,367	24,823
Notional Amount	907,000	907,000
Derivatives designated as hedging instruments: | Fair Value Hedge | Interest Rate Swaps
Derivative [Line Items]
Other Assets	14,454	7,658
Other Liabilities	1,403	1,306
Notional Amount	133,106	133,209
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Assets	45,853	24,832
Other Liabilities	46,127	24,715
Notional Amount	1,029,964	727,572
Derivatives not designated as hedging instruments: | Interest Rate Swaps
Derivative [Line Items]
Other Assets	44,861	24,628
Other Liabilities	44,858	24,623
Notional Amount	756,274	654,134
Derivatives not designated as hedging instruments: | Mortgage Banking Derivatives
Derivative [Line Items]
Other Assets	992	204
Other Liabilities	1,269	92
Notional Amount	$ 273,690	$ 73,438