Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net loss	$ (31,547)	$ (48,376)	$ (45,941)	$ (60,521)
Other comprehensive income (loss):
Foreign currency translation, net of tax of zero, $3,656, zero and $3,656	2,901	8,230	(19,547)	17,979
Derivative activity:
Effective portion of change in fair market value of derivatives, net of tax of ($2,273), ($1,285), ($1,227) and ($1,344), respectively	12,152	1,920	20,888	(2,498)
Reclassifications to net loss due to de-designation of interest rate derivatives, net of zero tax impact	0	2,207	(1,529)	2,207
Reclassifications to net loss, net of tax impact of $279, $351, $618 and $838 respectively	819	2,540	3,437	7,023
Total change in derivative activity	12,971	6,667	22,796	6,732
Proportionate share of equity investee’s derivative activity:
Effective portion of change in fair market value of derivatives, net of tax of ($1,505), ($2,075), ($1,980) and ($2,360), respectively	4,175	5,756	5,492	6,546
Reclassifications to net loss, net of tax of $375, $672, $1,273 and $2,333, respectively	1,041	1,863	3,530	6,471
Total change in proportionate share of equity investee's derivative activity	5,216	7,619	9,022	13,017
Total other comprehensive income, net of tax	21,088	22,516	12,271	37,728
Comprehensive loss	(10,459)	(25,860)	(33,670)	(22,793)
Less comprehensive income (loss) attributable to noncontrolling interest:
Net loss attributable to noncontrolling interest	(18,952)	(18,548)	(201,986)	(50,566)
Foreign currency translation, net of zero tax impact	1,636	(718)	(1,277)	(718)
Derivative activity:
Effective portion of change in fair market value of derivatives, net of tax of $12, ($267), ($96) and ($166), respectively	2,245	763	3,226	489
Reclassifications to net gain due to de-designation of interest rate derivatives, net of zero tax impact	0	0	(447)	0
Reclassifications to net loss, net of tax of $38, $86, $41 and $148, respectively	167	244	794	411
Total change in derivative activity	2,412	1,007	3,573	900
Comprehensive loss attributable to noncontrolling interest	(14,904)	(18,259)	(199,690)	(50,384)
Comprehensive income (loss) attributable to Pattern Energy	$ 4,445	$ (7,601)	$ 166,020	$ 27,591