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	Dec. 31, 2019
Pension and other post retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 820	$ 651	$ 2,460	$ 1,954
Tax effect	(197)	(158)	(591)	(477)
Amortization of actuarial losses included in net periodic pension cost, net	623	493	1,869	1,477
Amortization of prior service cost included in net periodic pension cost, gross	15	(28)	46	(86)
Tax effect	(4)	6	(11)	21
Amortization of prior service cost included in net periodic pension cost, net	11	(22)	35	(65)
Other comprehensive income related to pension and other post-retirement obligations, net of taxes	634	471	1,904	1,412
Unrealized (losses) gains on available-for-sale securities:
Net unrealized holding (losses) gains arising during period, gross	(8,821)	8,756	121,439	66,208
Tax effect	2,118	(2,136)	(29,155)	(16,157)
Net unrealized holding (losses) gains arising during period, net	(6,703)	6,620	92,284	50,051
Reclassification adjustment for net gains included in net income, gross	0	0	0	(4,882)
Tax effect	0	0	0	1,194
Reclassification adjustment for net gains included in net income, net	0	0	0	(3,688)
Other comprehensive income related to unrealized (losses) gains on available-for-sale securities, net of taxes	(6,703)	6,620	92,284	46,363
Other comprehensive (loss) income, net of tax	(6,069)	7,091	94,188	47,775
Net income	42,809	39,218	118,191	126,179
Comprehensive income	36,740	$ 46,309	212,379	$ 173,954
Accumulated Other Comprehensive Income (Loss) By Component:
Unrealized (loss) for pension and other post-retirement obligations	(43,669)		(43,669)		$ (46,175)
Tax effect	10,691		10,691		11,293
Net unrealized (loss) for pension and other post-retirement obligations	(32,978)		(32,978)		(34,882)
Unrealized gain on available-for-sale securities	154,316		154,316		32,877
Tax effect	(37,376)		(37,376)		(8,221)
Net unrealized gain on available-for-sale securities	116,940		116,940		24,656
Accumulated other comprehensive income (loss)	$ 83,962		$ 83,962		$ (10,226)