Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Allowances for contract receivables	$ 799	$ 930
Allowances for employee advances and miscellaneous receivables	500	681
Accumulated amortization on intangible assets	$ 36,128	$ 35,708
Common stock, par value (usd per share)	$ 0	$ 0
Common stock, stated value per share (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (shares)	50,000,000	50,000,000
Common stock, shares issued (shares)	21,845,920	22,681,656
Common stock, shares outstanding (shares)	21,845,920	22,681,656