Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Taxes
Statutory federal income tax rate (as a percent)			34.00%
Income tax at federal rate	$ 818	$ 373	$ 906	$ 914
Increase (decrease) resulting from:
State income taxes, net of federal income tax	134	46	146	113
Permanent difference for compensation limitation		104		228
Expense reflected in tax basis	144	211	160	211
Other permanent differences	101	49	105	154
Capital goods excise tax credit	(237)	(140)	(251)	(363)
Total income tax provision	960	643	1,066	1,257
Unrecognized Tax Benefits	0		0
Interest or penalties related to tax assessments recognized	$ 0	$ 0	$ 0	$ 0