Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 725	$ 868
Property and equipment, accumulated depreciation	$ 147,086	$ 143,216
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares issued (in shares)	11,380,982	11,332,841
Common Stock, shares outstanding (in shares)	11,380,982	11,332,841