CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 13,493	$ 14,273
Other comprehensive income:
Net change in unrealized gains on available-for-sale securities, net of tax	18,930	10,899
Net change in unrealized loss on cash flow hedging derivatives, net of tax	(754)	(831)
Net gain on postretirement plans, net of tax	133	48
Other comprehensive income	18,309	10,116
Comprehensive Income	$ 31,802	$ 24,389