Accumulated Other Comprehensive Income (Loss) - Significant Amounts Reclassified Out of Each Component of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net gain on sales of available for sale securities	$ 82	$ 854
Compensation and employee benefits	(8,630)	(8,223)
Tax effect	(1,248)	(1,141)
Net income	3,986	4,154
Amount Reclassified From Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net income	(91)	449
Amount Reclassified From Accumulated Other Comprehensive Income | Unrealized gains and losses on available-for-sale securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Net gain on sales of available for sale securities	82	854
Tax effect	(28)	(290)
Net income	54	564
Amount Reclassified From Accumulated Other Comprehensive Income | Amortization of defined benefit pension items
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and employee benefits	(220)	(174)
Tax effect	75	59
Net income	(145)	(115)
Amount Reclassified From Accumulated Other Comprehensive Income | Prior service costs
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and employee benefits	23	31
Amount Reclassified From Accumulated Other Comprehensive Income | Actuarial gains
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Compensation and employee benefits	$ (243)	$ (205)