Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Other Assets
Derivative [Line Items]
Cash flow hedge interest rate caps and swaps	$ 39	$ 294
Fair value hedge interest rate swaps	792	852
Total derivatives designated as hedging instruments	831	1,146
Mortgage banking derivatives	3,491
Interest rate swaps	11,087	4,065
Other Liabilities
Derivative [Line Items]
Cash flow hedge interest rate caps and swaps	18,510	15,649
Fair value hedge interest rate swaps	2,317	2,140
Total derivatives designated as hedging instruments	20,827	17,789
Mortgage banking derivatives	2,807
Interest rate swaps	10,400	4,065
Interest Rate Swap | Other Assets
Derivative [Line Items]
Interest rate swaps	7,596	4,065
Interest Rate Swap | Other Liabilities
Derivative [Line Items]
Interest rate swaps	$ 7,593	$ 4,065