Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 10,409	$ 10,715
Net unrealized holding gain on securities available for sale	8,035	3,309
Reclassification adjustments for net gain recognized in income	0	(249)
Tax effect	(3,214)	(1,222)
Net unrealized gain on securities available for sale, net of tax	4,821	1,838
Amortization of net actuarial loss (gain)	33	(5)
Amortization of prior service cost (credit)	23	(22)
Tax effect	(23)	11
Amortization of net actuarial loss (gain) and prior service cost (credit) on pension and postretirement plans, net of tax	33	(16)
Other comprehensive income, net of tax	4,854	1,822
Comprehensive income	$ 15,263	$ 12,537