Commitments and Contingencies - Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2014
Interest rate caps and swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	41,911,000	50,752,000
Derivatives designated as hedging instruments:
Derivative [Line Items]
Notional Amount	714,999,000	1,040,209,000
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional Amount	1,322,305,000	727,572,000
Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	1,075,722,000	654,134,000
Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Notional Amount	246,583,000	73,438,000
Other Assets | Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Assets	802,000	8,942,000
Other Assets | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Assets	28,253,000	24,832,000
Other Assets | Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Assets	25,285,000	24,628,000
Other Assets | Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	2,968,000	204,000
Other Liabilities | Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Liabilities	16,627,000	26,129,000
Other Liabilities | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Liabilities	27,450,000	24,715,000
Other Liabilities | Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Liabilities	25,284,000	24,623,000
Other Liabilities | Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Other Liabilities	2,166,000	92,000
Fair value hedge | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	7,999,000	133,209,000	$ 25,000,000
Fair value hedge | Other Assets | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Assets	0	7,658,000
Fair value hedge | Other Liabilities | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Liabilities	986,000	1,306,000
Cash flow hedge | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Notional Amount	707,000,000	907,000,000
Cash flow hedge | Other Assets | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Other Assets	802,000	1,284,000
Cash flow hedge | Other Liabilities | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Other Liabilities	$ 15,641,000	$ 24,823,000