CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income	$ 16,775	$ 14,488	$ 41,208	$ 41,965
Other comprehensive income:
Net change in unrealized gains on available-for-sale securities, net of tax	(586)	3,572	25,474	25,310
Net change in unrealized loss on cash flow hedging derivatives, net of tax	672	(41)	(30)	(1,918)
Net gain on postretirement plans, net of tax	133	49	399	145
Other comprehensive income	219	3,580	25,843	23,537
Comprehensive Income	$ 16,994	$ 18,068	$ 67,051	$ 65,502