CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Pension and other post retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 651	$ 304	$ 1,954	$ 910
Tax effect	(158)	(74)	(477)	(221)
Amortization of actuarial losses included in net periodic pension cost, net	493	230	1,477	689
Amortization of prior service cost included in net periodic pension cost, gross	(28)	(105)	(86)	(359)
Tax effect	6	25	21	87
Amortization of prior service cost included in net periodic pension cost, net	(22)	(80)	(65)	(272)
Initial projected benefit obligation recognized upon plan adoption, gross	0	(775)	0	(775)
Tax effect	0	189	0	189
Initial projected benefit obligation recognized upon plan adoption, net	0	(586)	0	(586)
Other comprehensive income (loss) related to pension and other post-retirement obligations, net of taxes	471	(436)	1,412	(169)
Unrealized gains (losses) on available-for-sale securities:
Net unrealized holding gains (losses) arising during period, gross	8,756	(20,094)	66,208	(76,705)
Tax effect	(2,136)	4,879	(16,157)	18,639
Net unrealized holding gains (losses) arising during period, net	6,620	(15,215)	50,051	(58,066)
Reclassification adjustment for net gains included in net income, gross	0	0	(4,882)	0
Tax effect	0	0	1,194	0
Reclassification adjustment for net gains included in net income, net	0	0	(3,688)	0
Reclassification of other comprehensive income due to change in accounting principle - equity securities	0	0	0	(208)
Other comprehensive income/(loss) related to unrealized gains (losses) on available-for-sale securities, net of taxes	6,620	(15,215)	46,363	(58,274)
Other comprehensive income (loss), net of tax	7,091	(15,651)	47,775	(58,443)
Net income	39,218	43,106	126,179	127,818
Comprehensive income	46,309	$ 27,455	173,954	$ 69,375
Accumulated Other Comprehensive Income (Loss) By Component:
Unrealized (loss) for pension and other post-retirement obligations	(41,629)		(41,629)		$ (43,497)
Tax effect	10,204		10,204		10,660
Net unrealized (loss) for pension and other post-retirement obligations	(31,425)		(31,425)		(32,837)
Unrealized gain (loss) on available-for-sale securities	45,097		45,097		(16,229)
Tax effect	(10,994)		(10,994)		3,969
Reclassification of other comprehensive income due to change in accounting principle - equity securities	(208)		(208)		(208)
Net unrealized gain (loss) on available-for-sale securities	33,895		33,895		(12,468)
Accumulated other comprehensive income (loss)	$ 2,470		$ 2,470		$ (45,305)