CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Pension and other post retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 652	$ 303	$ 1,303	$ 606
Tax effect	(160)	(74)	(319)	(147)
Amortization of actuarial losses included in net periodic pension cost, net	492	229	984	459
Amortization of prior service cost included in net periodic pension cost, gross	(29)	(127)	(58)	(254)
Tax effect	8	31	15	62
Amortization of prior service cost included in net periodic pension cost, net	(21)	(96)	(43)	(192)
Other comprehensive income related to pension and other post-retirement obligations, net of taxes	471	133	941	267
Unrealized gains (losses) on available-for-sale securities:
Net unrealized holding gains (losses) arising during period, gross	33,547	(14,816)	57,452	(56,632)
Tax effect	(8,189)	3,625	(14,021)	13,781
Net unrealized holding gains (losses) arising during period, net	25,358	(11,191)	43,431	(42,851)
Reclassification adjustment for net gains included in net income, gross	(4,882)	0	(4,882)	0
Tax effect	1,194	0	1,194	0
Reclassification adjustment for net gains included in net income, net	(3,688)	0	(3,688)	0
Reclassification of other comprehensive income due to change in accounting principle - equity securities	0	(208)	0	(208)
Other comprehensive income/(loss) related to unrealized gains (losses) on available-for-sale securities, net of taxes	21,670	(11,399)	39,743	(43,059)
Other comprehensive income (loss), net of tax	22,141	(11,266)	40,684	(42,792)
Net income	45,015	44,606	86,961	84,712
Comprehensive income	67,156	$ 33,340	127,645	$ 41,920
Accumulated Other Comprehensive Income By Component:
Unrealized (loss) for pension and other post-retirement obligations	(42,252)		(42,252)		$ (43,497)
Tax effect	10,356		10,356		10,660
Net unrealized (loss) for pension and other post-retirement obligations	(31,896)		(31,896)		(32,837)
Unrealized gain (loss) on available-for-sale securities	36,341		36,341		(16,229)
Tax effect	(9,066)		(9,066)		3,969
Reclassification of other comprehensive income due to change in accounting principle - equity securities	0		0		(208)
Net unrealized gain (loss) on available-for-sale securities	27,275		27,275		(12,468)
Accumulated other comprehensive (loss)	$ (4,621)		$ (4,621)		$ (45,305)