Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	$ 52,839	$ 47,990
Other comprehensive income before reclassification	(820)	(315)
Amounts reclassified from accumulated other comprehensive income	91	(449)
Total other comprehensive loss	(729)	(764)
Balance at end of period	54,073	52,839
Unrealized Gains and Losses on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(248)	198
Other comprehensive income before reclassification	(377)	118
Amounts reclassified from accumulated other comprehensive income	(54)	(564)
Total other comprehensive loss	(431)	(446)
Balance at end of period	(679)	(248)
Defined Benefit Pension Items
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(3,514)	(3,196)
Other comprehensive income before reclassification	(443)	(433)
Amounts reclassified from accumulated other comprehensive income	145	115
Total other comprehensive loss	(298)	(318)
Balance at end of period	(3,812)	(3,514)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at beginning of period	(3,762)	(2,998)
Balance at end of period	$ (4,491)	$ (3,762)