CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 3,191	$ 3,545
Current portion of long-term debt, net of debt issuance cost	530	483
Long-term debt, net of debt issuance cost	$ 2,941	$ 3,350
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, authorized	300,000,000	300,000,000
Common stock, issued	190,374,862	190,374,801
Common stock, outstanding	147,167,622	147,167,561
Treasury stock, shares	43,207,240	43,207,240