CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Unrealized holding gain (loss) on securities available for sale arising during the period, tax	$ (20)	$ 8,001	$ (6,841)
Unrealized loss on securities transferred to held-to-maturity, tax	0	0	(1,786)
Unrealized gain (loss) on securities available for sale for which a portion of an other than temporary impairment has been recognized in income, tax	0	(995)	(767)
Unrealized gain (loss) on cash flow hedges arising during the period, tax	(588)	(1,397)	831
Reclassification adjustment for net losses (gains) included in net income, tax	435	760	(157)
Defined benefit pension plans, tax	$ (1,187)	$ 4,264	$ (6,382)