Derivative Instruments and Hedging Activities - Consolidated Statements of Financial Condition Related to Fair Value of Derivative Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Other Assets [Member] | Derivatives designated as hedging instruments [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	$ 405	$ 675
Other Assets [Member] | Derivatives designated as hedging instruments [Member] | Cash flow hedge interest rate caps and swaps [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	27	23
Other Assets [Member] | Derivatives designated as hedging instruments [Member] | Fair value hedge interest rate swaps [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	378	652
Other Assets [Member] | Derivatives not designated as hedging instrument [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	7,020	7,241
Other Assets [Member] | Derivatives not designated as hedging instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	4,631	7,002
Other Assets [Member] | Derivatives not designated as hedging instrument [Member] | Mortgage Banking Derivatives [Member]
Derivative [Line Items]
Asset Derivatives, Fair Value	2,389	239
Other Liabilities [Member] | Derivatives designated as hedging instruments [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	13,083	19,395
Other Liabilities [Member] | Derivatives designated as hedging instruments [Member] | Cash flow hedge interest rate caps and swaps [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	11,408	17,198
Other Liabilities [Member] | Derivatives designated as hedging instruments [Member] | Fair value hedge interest rate swaps [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	1,675	2,197
Other Liabilities [Member] | Derivatives not designated as hedging instrument [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	5,888	7,199
Other Liabilities [Member] | Derivatives not designated as hedging instrument [Member] | Interest rate swaps [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	4,631	6,999
Other Liabilities [Member] | Derivatives not designated as hedging instrument [Member] | Mortgage Banking Derivatives [Member]
Derivative [Line Items]
Liability Derivatives, Fair Value	$ 1,257	$ 200