Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 7,034	$ 5,775
Preferred stock, undesignated, par (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, undesignated, shares authorized	2,000,000	2,000,000
Preferred stock, undesignated, shares outstanding	0	0
Common stock, par (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares issues	32,467,823	32,462,542
Common stock, shares outstanding	32,467,823	32,462,542