Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current portion of restricted cash	$ 123,680	$ 79,294
Prepaid expenses and other current assets	92,603	102,555
Power plants, net	1,345,793	1,355,362
Intangible assets, net	82,177	82,450
Current portion of long-term debt	320,355	327,459
Accrued expenses and other current liabilities	163,835	119,179
Other long-term liabilities	1,103	6,810
Deferred tax liabilities	$ 54,340	$ 52,106
Preferred stock, par value (in dollars 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
Common Class A
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	2,750,000,000	2,750,000,000
Common stock, shares issued	111,849,859	113,253,681
Common stock, shares outstanding	111,849,859	113,253,681
Common Class B
Common stock, par value (in dollars 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 (in dollars 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
Current portion of restricted cash	$ 68,534	$ 64,786
Prepaid expenses and other current assets	79,379	85,501
Power plants, net	375,039	431,686
Intangible assets, net	54,596	56,077
Current portion of long-term debt	308,948	314,928
Accrued expenses and other current liabilities	42,907	44,633
Other long-term liabilities	48,155	5,813
Deferred tax liabilities	$ 35,260	$ 40,817