Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Pre-Tax Amount
Other Comprehensive (Loss)/Income, Pre-Tax Amount		$ (2,931)	$ 391	$ (13,378)		$ 1,816
Tax (Expense) Benefit
Other Comprehensive (Loss)/Income, Tax (Expense) Benefit		623	(137)	2,841		(636)
Net of Tax Amount
Other Comprehensive (Loss)/Income, Net of Tax Amount		(2,308)	254	(10,537)		1,180
Accumulated Net Investment Gain (Loss) Attributable to Parent
Pre-Tax Amount
Change in net unrealized (losses)/gains on debt securities available-for-sale	[1]	(3,521)	(148)	(15,291)		4,186
Reclassification adjustment for net (gains)/losses on debt securities available-for-sale included in net income		0	0	0	[2]	(3,987)	[2]
Tax (Expense) Benefit
Change in net unrealized (losses)/gains on debt securities available-for-sale	[1]	748	52	3,247		(1,470)
Reclassification adjustment for net (gains)/losses on debt securities available-for-sale included in net income		0	0	0	[2]	1,400	[2]
Net of Tax Amount
Change in net unrealized (losses)/gains on debt securities available-for-sale	[1]	(2,773)	(96)	(12,044)		2,716
Reclassification adjustment for net (gains)/losses on debt securities available-for-sale included in net income		0	0	0	[2]	(2,587)	[2]
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Pre-Tax Amount
Other Comprehensive (Loss)/Income, Pre-Tax Amount		590	539	1,913		1,617
Tax (Expense) Benefit
Other Comprehensive (Loss)/Income, Tax (Expense) Benefit		(125)	(189)	(406)		(566)
Net of Tax Amount
Other Comprehensive (Loss)/Income, Net of Tax Amount		$ 465	$ 350	$ 1,507		$ 1,051

[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 period ended September 30, 2017.

[2] Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows: the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.