Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Receivables, allowance	$ 2,365	$ 2,336
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized shares	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized shares	150,000,000	150,000,000
Common stock, shares issued	33,891,000	33,891,000
Common stock, shares outstanding	33,458,000	33,458,000
Treasury stock, shares, at cost	3,351,000	3,351,000