Other Data (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
State income tax expense:
Texas gross margins tax	$ 562	$ 528	$ 694
Other	2	37	58
Total state income tax expense	564	565	752
State income tax payments, net of refunds and collections	$ 544	758	$ 593
Income tax expense in discontinued operations		$ 50