ACQUISITIONS (Details 2) (USD $) In Thousands, unless otherwise specified							12 Months Ended
	Dec. 31, 2013	Nov. 15, 2013	Dec. 31, 2012	Nov. 09, 2012		Dec. 31, 2011	Dec. 31, 2013 Central Bankcorp, Inc. [Member]	Dec. 31, 2012 Central Bankcorp, Inc. [Member]	Nov. 15, 2013 Central Bankcorp, Inc. [Member]
Business Acquisition [Line Items]
Net interest income after provision for loan losses							$ 178,556	$ 162,781
Contractually required principal and interest at acquisition		4,440		47,548	[1]				4,440
Contractual cash flows not expected to be collected		(1,296)		(8,733)					(1,296)
Expected cash flows at acquisition		3,144		38,815	[1]				3,144
Interest component of expected cash flows	(2,514)	(386)	(2,464)	(3,095)		0			(386)
Basis in PCI loans at acquisition - estimated fair value		2,758		35,720			2,747		2,758
Net income							$ 55,103	$ 44,133

[1] Reflective of anticipated prepayments.