ACQUISITIONS (Details 2) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Nov. 15, 2013	Dec. 31, 2012	Nov. 09, 2012
Business Acquisition [Line Items]
Contractually required principal and interest at acquisition			$ 4,440		$ 47,548	[1]
Contractual cash flows not expected to be collected			(1,296)		(8,733)
Expected cash flows at acquisition			3,144		38,815	[1]
Interest component of expected cash flows	(2,974)	(2,514)	(386)	(2,464)	(3,095)
Basis in PCI loans at acquisition - estimated fair value			2,758		35,720
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
Contractual cash flows not expected to be collected			(1,296)
Expected cash flows at acquisition			3,144
Interest component of expected cash flows			(386)
Basis in PCI loans at acquisition - estimated fair value			2,758
Net income	$ 55,103	$ 44,133

[1] Reflective of anticipated prepayments.