Common and Preferred Stock (Detail) - USD ($)				1 Months Ended	12 Months Ended
	Jun. 19, 2015	Jan. 01, 2012	Jun. 29, 2009	Jul. 31, 2008	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2010	Dec. 31, 2008	Jun. 30, 2025	Dec. 31, 2007
Common Stock [Line Items]
Common stock, shares authorized					332,023,233	332,023,233
Maximum voluntary optional cash payments made by shareholders to purchase common shares			$ 100,000
Warrant exercise period		10 years
Number of common stock issued upon exercise of warrant		489,000
Exercise price of warrant (in usd per share)		$ 11.30
Series A Preferred Stock [Member]
Common Stock [Line Items]
Stock issued (in shares)	4,600,000				4,600,000
Liquidation preference per share (usd per share)	$ 25
Fixed dividend rate per annum (as a percentage)	6.25%
Proceeds from issuance of preferred stock, net of issuance costs	$ 111,600,000
Series A Preferred Stock [Member] | LIBOR [Member] | Forecast [Member]
Common Stock [Line Items]
Spread on variable dividend rate per annum (as a percentage)										3.85%
Dividend Reinvestment Plan [Member]
Common Stock [Line Items]
Number of shares reissued from treasury stock					713,000	499,000	775,000
Proceeds from treasury stock reissued					$ 7,000,000	$ 5,000,000	$ 7,600,000
Parent Company [Member]
Common Stock [Line Items]
Number of shares repurchased					387,000	174,000	78,000
Number of shares authorized to repurchase											4,700,000
Number of shares repurchased during the period					0	0	0
Average price of shares purchased (in usd per share)					$ 9.95	$ 9.96	$ 9.91
Parent Company [Member] | U.S. Treasury Warrants [Member]
Common Stock [Line Items]
Exercise price of warrant (in usd per share)								$ 16.12
Amount of shares each warrant entitles buyer to purchase								1.1030
Parent Company [Member] | Greater Community Bancorp Warrants [Member]
Common Stock [Line Items]
Warrants issued (in shares)				918,000
Parent Company [Member] | Dividend Reinvestment Plan [Member]
Common Stock [Line Items]
Common stock, shares authorized			10,000,000
Parent Company [Member] | Warrants [Member] | U.S. Treasury Warrants [Member]
Common Stock [Line Items]
Number of shares repurchased									2,500,000