Stockholders' Equity (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Unrealized Gain (Loss) on Securities
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	[1]	$ (1,936)	$ (591)
Other comprehensive income, before reclassifications	[1]	493	2,006
Amounts reclassified from accumulated other comprehensive income (loss)	[1]	0	(472)
Current period other comprehensive income, before tax	[1]	493	1,534
Income tax expense	[1]	(187)	(583)
Current period other comprehensive income, net of tax	[1]	306	951
Balance at end of period	[1]	(1,630)	360
Unrecognized Net Pension and Postretirement Costs
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period	[2]	(1,865)	(1,427)
Other comprehensive income, before reclassifications	[2]	22	21
Amounts reclassified from accumulated other comprehensive income (loss)	[2]	0	0
Current period other comprehensive income, before tax	[2]	22	21
Income tax expense	[2]	(8)	(8)
Current period other comprehensive income, net of tax	[2]	14	13
Balance at end of period	[2]	(1,851)	(1,414)
Accumulated Other Comprehensive (Loss) Income
Accumulated Other Comprehensive Income (Loss)
Balance at beginning of period		(3,801)	(2,018)
Other comprehensive income, before reclassifications		515	2,027
Amounts reclassified from accumulated other comprehensive income (loss)		0	(472)
Current period other comprehensive income, before tax		515	1,555
Income tax expense		(195)	(591)
Current period other comprehensive income, net of tax		320	964
Balance at end of period		(3,481)	(1,054)
Balance at beginning of period		(3,801)
Current period other comprehensive income, net of tax		320	$ 964
Balance at end of period		$ (3,481)

[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.