Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Cash and cash equivalents, including consolidated variable interest entities of $37,090 in 2016 and $19,957 in 2015	$ 921,510,000	$ 922,318,000
Current portion of restricted cash, including consolidated variable interest entities of $49,023 in 2016 and $46,321 in 2015	76,618,000	119,151,000
Prepaid expenses and other current assets, including consolidated variable interest entities of $105,920 in 2016 and $123,876 in 2015	112,071,000	139,335,000
Power plants, net, including consolidated variable interest entities of $610,207 in 2016 and $460,042 in 2015	1,305,030,000	1,206,604,000
Intangible assets, net, including consolidated variable interest entities of $52,204 in 2016 and $51,159 in 2015	71,457,000	70,630,000
Other assets, including consolidated variable interest entities of zero in 2016 and $8,537 in 2015	46,773,000	51,809,000
Current portion of long-term debt, including consolidated variable interest entities of $327,707 in 2016 and $326,535 in 2015	348,806,000	319,498,000
Accrued expenses and other current liabilities, including consolidated variable interest entities of $40,935 in 2016 and $15,496 in 2015	118,417,000	129,437,000
Other long-term liabilities, including consolidated variable interest entities of $26,863 in 2016 and $24,238 in 2015	1,380,000	1,455,000
Deferred tax liabilities, including consolidated variable interest entities of $34,997 in 2016 and $37,295 in 2015	$ 42,273,000	$ 39,482,000
Common Class A
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,750,000,000	2,750,000,000
Common stock, shares issued	113,127,989	114,630,318
Common stock, shares outstanding	113,127,989	114,630,318
Common Class B
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	61,343,054	61,343,054
Common stock, shares outstanding	61,343,054	61,343,054
Common Class B1
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized	550,000,000	550,000,000
Common stock, shares issued	0	0
Common stock, shares outstanding	0	0
Variable interest entities
Cash and cash equivalents, including consolidated variable interest entities of $37,090 in 2016 and $19,957 in 2015	$ 37,090,000	$ 19,957,000
Current portion of restricted cash, including consolidated variable interest entities of $49,023 in 2016 and $46,321 in 2015	49,023,000	46,321,000
Prepaid expenses and other current assets, including consolidated variable interest entities of $105,920 in 2016 and $123,876 in 2015	105,920,000	123,876,000
Power plants, net, including consolidated variable interest entities of $610,207 in 2016 and $460,042 in 2015	610,207,000	460,042,000
Intangible assets, net, including consolidated variable interest entities of $52,204 in 2016 and $51,159 in 2015	52,204,000	51,159,000
Other assets, including consolidated variable interest entities of zero in 2016 and $8,537 in 2015	0	8,537
Current portion of long-term debt, including consolidated variable interest entities of $327,707 in 2016 and $326,535 in 2015	327,707,000	326,535,000
Accrued expenses and other current liabilities, including consolidated variable interest entities of $40,935 in 2016 and $15,496 in 2015	40,935,000	15,496,000
Other long-term liabilities, including consolidated variable interest entities of $26,863 in 2016 and $24,238 in 2015	26,863,000	24,238,000
Deferred tax liabilities, including consolidated variable interest entities of $34,997 in 2016 and $37,295 in 2015	$ 34,997,000	$ 37,295,000