CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Pension and other post-retirement obligations:
Amortization of actuarial losses included in net periodic pension cost, gross	$ 265	$ 375
Tax effect	(102)	(144)
Amortization of actuarial losses included in net periodic pension cost, net	163	231
Amortization of prior service cost included in net periodic pension cost, gross	(31)	(34)
Tax effect	12	13
Amortization of prior service cost included in net periodic pension cost, net	(19)	(21)
Other comprehensive income related to pension and other post-retirement obligations, net of taxes	144	210
Unrealized gains on available-for-sale securities:
Net unrealized holding gains arising during period, gross	3,893	67,257
Tax effect	(1,526)	(25,415)
Net unrealized holding gains arising during period, net	2,367	41,842
Other comprehensive income related to unrealized gains on available-for-sale securities, net of taxes	2,367	41,842
Other comprehensive income, net of tax	2,511	42,052
Net income	26,257	24,403
Comprehensive income	28,768	$ 66,455
Accumulated Other Comprehensive Income By Component:
Unrealized loss for pension and other postretirement obligations	(28,735)		$ (28,969)
Tax effect	10,918		11,008
Net unrealized loss for pension and other postretirement obligations	(17,817)		(17,961)
Unrealized gain on available-for-sale securities	45,686		41,793
Tax effect	(17,515)		(15,989)
Net unrealized gain on available-for-sale securities	28,171		25,804
Accumulated other comprehensive income	$ 10,354		$ 7,843