Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 8,615	$ 9,175
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	7,500,000	7,500,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	123,863,782	123,984,527
Common stock, shares outstanding	123,863,782	123,984,527