Accumulated Other Comprehensive Loss - Summary of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			$ 1,878,744	$ 1,775,762
Total other comprehensive income (loss), net of tax	$ 10,270	$ (8,753)	15,212	(21,847)
Ending Balance	2,127,714	1,645,526	2,127,714	1,645,526
Less: accumulated other comprehensive loss attributable to noncontrolling interest	1,175,430	916,670	1,175,430	916,670	$ 891,246	$ 944,262
Accumulated other comprehensive loss attributable to Pattern Energy	952,284		952,284		$ 987,498
Foreign Currency [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(43,500)	(48,285)
Other comprehensive income (loss) before reclassifications			9,749	11,642
Amounts reclassified from accumulated other comprehensive loss			0	0
Total other comprehensive income (loss), net of tax			9,749	11,642
Ending Balance	(33,751)	(36,643)	(33,751)	(36,643)
Less: accumulated other comprehensive loss attributable to noncontrolling interest	0	0	0	0
Accumulated other comprehensive loss attributable to Pattern Energy	(33,751)	(36,643)	(33,751)	(36,643)
Effective Portion of Change in Fair Value of Derivatives [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(12,751)	(13,462)
Other comprehensive income (loss) before reclassifications			(4,418)	(30,661)
Amounts reclassified from accumulated other comprehensive loss			4,483	5,623
Total other comprehensive income (loss), net of tax			65	(25,038)
Ending Balance	(12,686)	(38,500)	(12,686)	(38,500)
Less: accumulated other comprehensive loss attributable to noncontrolling interest	(489)	(1,688)	(489)	(1,688)
Accumulated other comprehensive loss attributable to Pattern Energy	(12,197)	(36,812)	(12,197)	(36,812)
Proportionate Share of Equity Investee's OCI [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(6,498)	(12,131)
Other comprehensive income (loss) before reclassifications			790	(11,008)
Amounts reclassified from accumulated other comprehensive loss			4,608	2,557
Total other comprehensive income (loss), net of tax			5,398	(8,451)
Ending Balance	(1,100)	(20,582)	(1,100)	(20,582)
Less: accumulated other comprehensive loss attributable to noncontrolling interest	0	0	0	0
Accumulated other comprehensive loss attributable to Pattern Energy	(1,100)	(20,582)	(1,100)	(20,582)
AOCI [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance			(62,749)	(73,878)
Other comprehensive income (loss) before reclassifications			6,121	(30,027)
Amounts reclassified from accumulated other comprehensive loss			9,091	8,180
Total other comprehensive income (loss), net of tax			15,212	(21,847)
Ending Balance	(47,537)	(95,725)	(47,537)	(95,725)
Less: accumulated other comprehensive loss attributable to noncontrolling interest	(489)	(1,688)	(489)	(1,688)
Accumulated other comprehensive loss attributable to Pattern Energy	$ (47,048)	$ (94,037)	$ (47,048)	$ (94,037)