Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Consolidated Statements of Comprehensive Income (Unaudited) [Abstract]
Net income	$ 10,930	$ 10,616	$ 31,803	$ 32,058
Net unrealized holding (loss) gain on securities available for sale	(125)	7,855	12,475	5,682
Reclassification adjustments for net gain recognized in income	0	0	(668)	(249)
Tax effect	50	(3,142)	(4,723)	(2,171)
Net unrealized (loss) gain on securities available for sale, net of tax	(75)	4,713	7,084	3,262
Amortization of net actuarial (gain) loss	(8)	43	(25)	53
Amortization of prior service cost	22	23	67	68
Tax effect	(6)	(26)	(17)	(48)
Amortization of net actuarial (gain) loss and prior service cost on pension and postretirement plans, net of tax	8	40	25	73
Other comprehensive (loss) income, net of tax	(67)	4,753	7,109	3,335
Comprehensive income	$ 10,863	$ 15,369	$ 38,912	$ 35,393