CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) [Abstract]
Net Income	$ 12,321	$ 11,989	$ 27,066	$ 23,146
Other comprehensive income (loss):
Change in unrealized holding loss on securities held-to-maturity and transferred securities	0	30	0	64
Change in unrealized holding loss on securities available-for-sale	(1,679)	104	(4,237)	224
Change in pension and other postretirement obligations	286	355	441	657
Change in unrealized gain on derivatives	560	(733)	2,576	(418)
Other comprehensive gain (loss) before income taxes	(833)	(244)	(1,220)	527
Deferred tax expense (benefit)	(292)	(111)	(404)	235
Other comprehensive income (loss), net of tax	(541)	(133)	(816)	292
Total comprehensive income	$ 11,780	$ 11,856	$ 26,250	$ 23,438