3. Recent Accounting Pronouncements (Details) - Statement of Cash Flows - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income	$ 205,747	$ 150,457	$ 266,839	$ 334,678
Equity in earnings of unconsolidated affiliates, net of tax	(4,045)	(4,474)	(5,462)	(6,851)
Remeasurement of monetary assets and liabilities			(12,464)	(3,711)
Excess tax benefit from share-based compensation arrangements				0
Noncash consideration from the sale of project assets			0	(20,084)
Accounts receivable, trade, unbilled and retainage			(328,556)	2,649
Prepaid expenses and other current assets			35,818	(47,386)
Project assets			969,264	(355,767)
Other assets			(16,453)	(11,045)
Income tax receivable and payable			6,416	(40,548)
Accrued expenses and other liabilities			(289,919)	(91,709)
Net cash used in operating activities			906,719	(61,673)
Change in restricted cash				0
Net cash used in investing activities			(403,959)	(163,774)
Excess tax benefit from share-based compensation arrangements				0
Payments of tax withholdings for restricted shares			(5,114)	(20,388)
Net cash provided by financing activities			151,606	462,270
Net increase in cash, cash equivalents and restricted cash			663,786	243,565
Cash, cash equivalents and restricted cash	$ 2,079,476	1,450,681	$ 2,079,476	1,450,681	$ 1,415,690	$ 1,207,116
Scenario, Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income		154,146		338,119
Equity in earnings of unconsolidated affiliates, net of tax		(10,474)		(25,647)
Remeasurement of monetary assets and liabilities				(4,054)
Excess tax benefit from share-based compensation arrangements				(18,169)
Noncash consideration from the sale of project assets				0
Accounts receivable, trade, unbilled and retainage				(22,791)
Prepaid expenses and other current assets				(47,300)
Project assets				(469,988)
Other assets				(11,234)
Income tax receivable and payable				(14,798)
Accrued expenses and other liabilities				(2,812)
Net cash used in operating activities				(100,573)
Change in restricted cash				44,171
Net cash used in investing activities				(119,603)
Excess tax benefit from share-based compensation arrangements				18,169
Payments of tax withholdings for restricted shares				0
Net cash provided by financing activities				500,827
Net increase in cash, cash equivalents and restricted cash				287,393
Cash, cash equivalents and restricted cash		1,414,219		1,414,219		1,126,826
Accounting Standards Update 2016-18 [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income				0
Equity in earnings of unconsolidated affiliates, net of tax				0
Remeasurement of monetary assets and liabilities				343
Excess tax benefit from share-based compensation arrangements				0
Noncash consideration from the sale of project assets				0
Accounts receivable, trade, unbilled and retainage				0
Prepaid expenses and other current assets				0
Project assets				0
Other assets				0
Income tax receivable and payable				0
Accrued expenses and other liabilities				0
Net cash used in operating activities				343
Change in restricted cash				(44,171)
Net cash used in investing activities				(44,171)
Excess tax benefit from share-based compensation arrangements				0
Payments of tax withholdings for restricted shares				0
Net cash provided by financing activities				0
Net increase in cash, cash equivalents and restricted cash				(43,828)
Cash, cash equivalents and restricted cash		36,462		36,462		80,290
Accounting Standards Update 2016-09 [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income		15,170		23,777
Equity in earnings of unconsolidated affiliates, net of tax		0		0
Remeasurement of monetary assets and liabilities				0
Excess tax benefit from share-based compensation arrangements				18,169
Noncash consideration from the sale of project assets				0
Accounts receivable, trade, unbilled and retainage				0
Prepaid expenses and other current assets				0
Project assets				0
Other assets				0
Income tax receivable and payable				(24,352)
Accrued expenses and other liabilities				20,963
Net cash used in operating activities				38,557
Change in restricted cash				0
Net cash used in investing activities				0
Excess tax benefit from share-based compensation arrangements				(18,169)
Payments of tax withholdings for restricted shares				(20,388)
Net cash provided by financing activities				(38,557)
Net increase in cash, cash equivalents and restricted cash				0
Cash, cash equivalents and restricted cash		0		0		0
Accounting Standards Update 2014-09 [Member] | Restatement Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net income		(18,859)		(27,218)
Equity in earnings of unconsolidated affiliates, net of tax		6,000		18,796
Remeasurement of monetary assets and liabilities				0
Excess tax benefit from share-based compensation arrangements				0
Noncash consideration from the sale of project assets				(20,084)
Accounts receivable, trade, unbilled and retainage				25,440
Prepaid expenses and other current assets				(86)
Project assets				114,221
Other assets				189
Income tax receivable and payable				(1,398)
Accrued expenses and other liabilities				(109,860)
Net cash used in operating activities				0
Change in restricted cash				0
Net cash used in investing activities				0
Excess tax benefit from share-based compensation arrangements				0
Payments of tax withholdings for restricted shares				0
Net cash provided by financing activities				0
Net increase in cash, cash equivalents and restricted cash				0
Cash, cash equivalents and restricted cash		$ 0		$ 0		$ 0