Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 4,773	$ 4,567
Preferred Stock, par value	$ 0.01	$ 0.01
Preferred Stock, shares authorized	100,000,000	100,000,000
Preferred Stock, shares outstanding	0	0
Common Stock, par value	$ 0.01	$ 0.01
Common Stock, shares authorized	2,000,000,000	2,000,000,000
Common Stock, shares issued	130,974,073	130,778,365
Common Stock, shares outstanding	124,302,318	130,695,274
Treasury stock, shares	6,671,755	83,091