Retirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Retirement Benefits [Abstract]
Automatic Annual Contribution Employees Hired Before January 1, 2009 Benefit Reduction Under Certain Amendments Minimum, percent			5.00%
Automatic Annual Contribution Employees Hired Before January 1, 2009 Due Benefit Reduction Under Certain Amendments Maximum, percent			7.00%
Employer's matching contribution to 401(k) of employees hired on or after January 1, 2009, percent			50.00%
Maximum annual contribution per employee, percent			3.00%
Funding and administrative costs of noncontributory defined benefit retirement plan and 401(k) plan [Abstract]
401(k) plan	$ 102	$ 81	$ 298	$ 241
Qualified noncontributory defined benefit retirement plan [Member]
Funding and administrative costs of noncontributory defined benefit retirement plan and 401(k) plan [Abstract]
Qualified noncontributory defined benefit retirement plan	267	272	789	712
Components of net periodic pension cost [Abstract]
Service cost	0	10	0	30
Interest cost	17	20	51	58
Amortization of unrecognized net loss	0	42	0	126
Net periodic pension cost	17	$ 72	51	$ 214
Recognized in accumulated other comprehensive income [Abstract]
Net actuarial (gain) loss	(16)		(16)		$ (16)
Past service cost	0		0		0
Total recognized in accumulated other comprehensive income (loss), net of tax	$ (16)		$ (16)		$ (16)