CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Unrealized holding gains/ (loss), tax	$ 10,551	$ (1,346)	$ (5,996)
Other-than-temporary impairment on securities included in net income, tax	(278)	(129)	(328)
Reclassification adjustment for (gains)/ losses included in net income, tax	1,904	271	(705)
Change in fair value of interest rate swaps, tax	(1,714)	(246)	1,506
Net gain/ (loss), tax	(10,716)	(6,112)	11,431
Amortization of prior service costs, tax	$ 812	$ 56	$ 56