Income Taxes - Significant Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for losses on loans	$ 3,939	$ 3,444
Pension obligations	2,102	2,402
Interest on nonaccrual loans	74	415
Unrealized loss on available-for-sale securities	91	72
Amortization of intangible assets	102	120
Deferred rent payable	153	194
Net operating losses	3,111	2,444
Charitable contribution carryforward	1,694	1,840
Other	235	162
Total gross deferred tax assets	11,501	11,093
Deferred tax liabilities:
Cumulative contribution in excess of net periodic benefit costs, net	3,120	3,134
Depreciation and amortization of premises and equipment	222	601
Deferred loan fees	438	317
Other	6	18
Total gross deferred tax liabilities	3,786	4,070
Valuation allowance	3,904	3,114
Net deferred tax assets	$ 3,811	$ 3,909