Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Current assets:
Allowance for doubtful accounts	$ 11,686	$ 10,826
Equity:
Preferred stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Preferred stock, shares authorized (in shares)	500	500
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock, shares authorized (in shares)	180,000	180,000
Common stock, shares issued (in shares)	89,069	89,343
Common stock, shares outstanding (in shares)	89,069	89,343