Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Accounts receivable, allowance	$ 6,276	$ 8,077
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, Authorized shares (in shares)	10,000,000	10,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, Authorized shares (in shares)	100,000,000	100,000,000
Common stock, issued (in shares)	16,268,000	16,109,000
Common stock, outstanding (in shares)	16,268,000	16,109,000