Commitments and Contingencies - Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Interest rate caps and swaps
Derivative [Line Items]
Other Assets	$ 0	$ 0
Other Liabilities	43,733	22,907
Derivatives designated as hedging instruments:
Derivative [Line Items]
Notional Amount	187,281	339,536
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional Amount	4,255,866	3,495,825
Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	4,113,106	3,390,578
Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Notional Amount	142,760	105,247
Other Assets | Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Assets	0	0
Other Assets | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Assets	158,532	48,979
Other Assets | Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Assets	158,382	48,642
Other Assets | Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Other Assets	150	337
Other Liabilities | Derivatives designated as hedging instruments:
Derivative [Line Items]
Other Liabilities	1,713	374
Other Liabilities | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Other Liabilities	42,213	23,307
Other Liabilities | Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Liabilities	42,020	22,533
Other Liabilities | Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Other Liabilities	193	774
Cash flow hedge | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Notional Amount	180,000	332,000
Cash flow hedge | Other Assets | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Other Assets	0	0
Cash flow hedge | Other Liabilities | Derivatives designated as hedging instruments: | Interest rate caps and swaps
Derivative [Line Items]
Other Liabilities	1,484	27
Fair value hedge | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	7,281	7,536
Fair value hedge | Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	10,400
Fair value hedge | Other Assets | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Assets	0	0
Fair value hedge | Other Liabilities | Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Other Liabilities	$ 229	$ 347