Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 7,348	$ 6,548
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	123,566,487	123,019,494
Common stock, shares outstanding	123,566,487	123,019,494