Consolidated Balance Sheets Balance Sheet Paranthetical - USD ($) shares in Thousands, $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets:
Allowance for doubtful accounts	$ 32,098	$ 30,308
Equity:
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	75,000	75,000
Common stock, shares issued	52,207	51,918
Common stock, shares outstanding	50,205	51,370
Common stock in treasury, at cost	1,575	123