CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) [Abstract]
Net Income	$ 11,989	$ 11,208	$ 23,146	$ 61,245
Other comprehensive income:
Change in unrealized holding loss on securities held-to-maturity and transferred securities	30	22	64	41
Change in unrealized holding loss on securities available-for-sale	104	47	224	62
Change in pension and other postretirement obligations	355	425	657	850
Change in unrealized gain on derivatives	(733)	(957)	(418)	(957)
Other comprehensive gain before income taxes	(244)	(463)	527	(4)
Deferred tax expense (benefit)	(111)	(209)	235	(2)
Other comprehensive income (loss), net of tax	(133)	(254)	292	(2)
Total comprehensive income	$ 11,856	$ 10,954	$ 23,438	$ 61,243