Stockholders' Equity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period		$ (6,099)
Total other comprehensive income (loss)		1,393	$ (1,673)
Balance at end of period		(4,706)
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	[1]	(3,455)	(2,500)
Other comprehensive (loss) income, before reclassifications	[1]	1,745	(2,171)
Amounts reclassified from accumulated other comprehensive (loss) income	[1]	0	0
Other comprehensive (loss) income, before tax	[1]	1,745	(2,171)
Income tax expense (benefit)	[1]	(367)	456
Total other comprehensive income (loss)	[1]	1,378	(1,715)
Balance at end of period	[1]	(2,077)	(4,215)
Unrecognized Net Pension and Postretirement Costs
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	[2]	(2,644)	(3,162)
Other comprehensive (loss) income, before reclassifications	[2]	19	54
Amounts reclassified from accumulated other comprehensive (loss) income	[2]	0	0
Other comprehensive (loss) income, before tax	[2]	19	54
Income tax expense (benefit)	[2]	(4)	(12)
Total other comprehensive income (loss)	[2]	15	42
Balance at end of period	[2]	(2,629)	(3,120)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period		(6,099)	(5,662)
Other comprehensive (loss) income, before reclassifications		1,764	(2,117)
Amounts reclassified from accumulated other comprehensive (loss) income		0	0
Other comprehensive (loss) income, before tax		1,764	(2,117)
Income tax expense (benefit)		(371)	444
Total other comprehensive income (loss)		1,393	(1,673)
Balance at end of period		$ (4,706)	$ (7,335)

[1] The pre-tax amounts reclassified from accumulated other comprehensive loss are included in gain on sale of investment securities in the consolidated statements of income.

[2] The pre-tax amounts reclassified from accumulated other comprehensive loss are included in the computation of net periodic pension cost.