Tax Effects on Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017	Dec. 31, 2016
Pre-Tax Amount
Other Comprehensive Loss	$ (497)		$ (6,267)	$ 4,075
Tax (Expense) Benefit
Other Comprehensive Loss	106		1,624	(1,402)
Net of Tax Amount
Other comprehensive income (loss), net of tax	(391)		(4,643)	2,673
Accumulated Net Investment Gain (Loss) Attributable to Parent
Pre-Tax Amount
Net change in unrealized (losses)/gains on debt securities available-for sale	(6,794)	[1]	(1,275)	(2,899)
Net available-for-sale securities losses reclassified into earnings	0		(3,000)	0
Tax (Expense) Benefit
Net change in unrealized (losses)/gains on debt securities available-for sale	1,449	[1]	448	1,006
Net available-for-sale securities losses reclassified into earnings	0		1,054	0
Net of Tax Amount
Net change in unrealized (losses)/gains on debt securities available-for sale	(5,345)	[1]	(827)	(1,893)
Net available-for-sale securities losses reclassified into earnings	0		(1,946)	0
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Pre-Tax Amount
Other Comprehensive Loss	6,297		(1,992)	6,974
Tax (Expense) Benefit
Other Comprehensive Loss	(1,343)		122	(2,408)
Net of Tax Amount
Other comprehensive income (loss), net of tax	$ 4,954		$ (1,870)	$ 4,566

[1] Due to the adoption of ASU No. 2016-01, net unrealized gains on marketable equity securities were reclassified from accumulated other comprehensive income to retained earnings during the three months ended March 31, 2018. The prior period data was not restated; as such, the change in unrealized gains on marketable securities is combined with the change in net unrealized gains on debt securities for the prior periods ended December 31, 2017 and 2016.