Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	6 Months Ended		12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2019	Jun. 30, 2017
Accumulated Other Comprehensive Loss [Abstract]
Unrealized gain on available-for-sale securities, net of tax		$ 290		$ 612
Net losses and past service liability for defined benefit plan, net of tax		(1,604)		(1,604)
Accumulated other comprehensive loss		$ (1,314)		$ (992)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Federal corporate tax rate		35.00%
Effective income tax rate reconciliation at federal statutory income tax rate		$ (259)
Forecast [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Federal corporate tax rate	21.00%		21.00%