Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accounts receivable, allowance	$ 1,044	$ 889
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	30,000,000	30,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock [Member]
Common stock - Class A, par value	$ 0.01	$ 0.01
Common stock - Class A, shares authorized	400,000,000	400,000,000
Common stock - Class A, shares issued	129,428,000	129,134,000
Common stock - Class A, shares outstanding	129,428,000	129,134,000