Derivative Instruments and Hedging Activities - Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Interest Rate Caps and Swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	71,889	50,752
Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Assets	286	8,942
Other Liabilities	26,909	26,129
Notional Amount	915,053	1,040,209
Derivatives designated as hedging instruments: | Cash Flow Hedge | Interest Rate Caps and Swaps
Derivative [Line Items]
Other Assets	286	1,284
Other Liabilities	25,636	24,823
Notional Amount	907,000	907,000
Derivatives designated as hedging instruments: | Fair Value Hedge | Interest Rate Swaps
Derivative [Line Items]
Other Assets	0	7,658
Other Liabilities	1,273	1,306
Notional Amount	8,053	133,209
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Assets	45,733	24,832
Other Liabilities	45,763	24,715
Notional Amount	1,276,637	727,572
Derivatives not designated as hedging instruments: | Interest Rate Swaps
Derivative [Line Items]
Other Assets	45,013	24,628
Other Liabilities	44,980	24,623
Notional Amount	824,736	654,134
Derivatives not designated as hedging instruments: | Mortgage Banking Derivatives
Derivative [Line Items]
Other Assets	720	204
Other Liabilities	783	92
Notional Amount	$ 451,901	$ 73,438