Pattern Energy 10-K 28 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
	Dec. 31, 2013	Jun. 28, 2013	Feb. 24, 2014	Feb. 25, 2014
			Class A common stock [Member]	Class B common stock [Member]
Document Information [Line Items]	'	'	'	'
Document Type	'10-K	'	'	'
Amendment Flag	'false	'	'	'
Document Period End Date	31-Dec-13	'	'	'
Document Fiscal Year Focus	'2013	'	'	'
Document Fiscal Period Focus	'FY	'	'	'
Trading Symbol	'PEGI	'	'	'
Entity Registrant Name	'Pattern Energy Group Inc.	'	'	'
Entity Central Index Key	'0001561660	'	'	'
Current Fiscal Year End Date	'--12-31	'	'	'
Entity Well-known Seasoned Issuer	'No	'	'	'
Entity Current Reporting Status	'Yes	'	'	'
Entity Voluntary Filers	'No	'	'	'
Entity Filer Category	'Non-accelerated Filer	'	'	'
Entity Common Stock, Shares Outstanding	'	'	35,548,051	15,555,000
Entity Public Float	'	$0	'	'

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013	Dec. 31, 2012
Current assets:	'	'
Cash and cash equivalents	$103,569,000	$17,574,000
Trade receivables	20,951,000	13,715,000
Related party receivable	167,000	'
Reimbursable interconnection costs	1,455,000	51,307,000
Derivative assets, current	13,937,000	17,177,000
Current deferred tax assets	573,000	'
Prepaid expenses and other current assets	13,927,000	13,794,000
Total current assets	154,579,000	113,567,000
Restricted cash	32,636,000	13,904,000
Turbine advances	'	44,150,000
Deferred development costs	'	26,544,000
Construction in progress	'	6,081,000
Property, plant and equipment - net of accumulated depreciation	1,476,142,000	1,668,302,000
Unconsolidated investments	107,055,000	36,218,000
Derivative assets	82,167,000	62,895,000
Deferred financing costs - net of accumulated amortization	35,792,000	42,654,000
Net deferred tax assets	2,017,000	4,940,000
Other assets	13,243,000	16,475,000
Total assets	1,903,631,000	2,035,730,000
Current liabilities:	'	'
Accounts payable and other accrued liabilities	15,550,000	7,750,000
Accrued construction costs	3,204,000	67,206,000
Related party payable	1,245,000	198,000
Accrued interest	495,000	559,000
Dividend payable	11,103,000	'
Contingent liabilities	'	8,001,000
Derivative liabilities, current	16,171,000	13,462,000
Current portion of long-term debt	48,851,000	137,258,000
Total current liabilities	96,619,000	234,434,000
Long-term debt	1,200,367,000	1,153,312,000
Derivative liabilities	7,439,000	35,326,000
Asset retirement obligations	20,834,000	19,056,000
Net deferred tax liabilities	9,930,000	3,662,000
Other long-term liabilities	438,000	528,000
Total liabilities	1,335,627,000	1,446,318,000
Equity:	'	'
Additional paid-in capital	489,388,000	1,000
Capital	'	545,471,000
Accumulated (loss) income	-13,336,000	2,903,000
Accumulated other comprehensive loss	-8,353,000	-34,264,000
Total equity before noncontrolling interest	468,210,000	514,111,000
Noncontrolling interest	99,794,000	75,301,000
Total equity	568,004,000	589,412,000
Total liabilities and equity	1,903,631,000	2,035,730,000
Class A common stock [Member]	'	'
Equity:	'	'
Common stock value	355,000	'
Class B common stock [Member]	'	'
Equity:	'	'
Common stock value	$156,000	'

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property, plant and equipment, accumulated depreciation	$179,778,000	$100,247,000
Deferred financing costs, accumulated amortization	$16,225,000	$9,311,000
Class A common stock [Member]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	35,530,786	100
Common stock, shares outstanding	35,530,786	100
Class B common stock [Member]	'	'
Common stock, par value	$0.01	'
Common stock, shares authorized	20,000,000	'
Common stock, shares issued	15,555,000	'
Common stock, shares outstanding	15,555,000	'

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue:	'	'	'
Electricity sales	$173,270,000	$101,835,000	$108,770,000
Energy derivative settlements	16,798,000	19,644,000	9,512,000
Unrealized (loss) gain on energy derivative	-11,272,000	-6,951,000	17,577,000
Related party revenue	911,000	'	'
Other revenue	21,866,000	'	'
Total revenue	201,573,000	114,528,000	135,859,000
Cost of revenue:	'	'	'
Project expense	57,677,000	34,843,000	31,343,000
Depreciation and accretion	83,180,000	49,027,000	39,424,000
Total cost of revenue	140,857,000	83,870,000	70,767,000
Gross profit	60,716,000	30,658,000	65,092,000
Operating expenses:	'	'	'
Development expense	'	174,000	704,000
General and administrative	4,819,000	858,000	866,000
Related party general and administrative	8,169,000	10,604,000	8,098,000
Total operating expenses	12,988,000	11,636,000	9,668,000
Operating income (loss)	47,728,000	19,022,000	55,424,000
Other income (expense):	'	'	'
Interest expense	-63,614,000	-36,502,000	-29,404,000
Equity in earnings (losses) in unconsolidated investments	7,846,000	-40,000	-205,000
Interest rate derivative settlements	-2,099,000	'	'
Unrealized gain (loss) on derivatives	15,601,000	-4,953,000	-345,000
Net gain on transactions	5,995,000	4,173,000	'
Related party income	665,000	'	'
Other income, net	2,496,000	1,320,000	1,125,000
Other income (expense)	-33,110,000	-36,002,000	-28,829,000
Net income (loss) before income tax	14,618,000	-16,980,000	26,595,000
Tax provision (benefit)	4,546,000	-3,604,000	689,000
Net income (loss)	10,072,000	-13,376,000	25,906,000
Net (loss) income attributable to noncontrolling interest	-6,887,000	-7,089,000	16,981,000
Net income (loss)	16,959,000	-6,287,000	8,925,000
Earnings per share information:	'	'	'
Less: Net income attributable to controlling interest prior to the IPO on October 2, 2013	-30,295,000	'	'
Net loss attributable to controlling interest subsequent to the IPO	-13,336,000	'	'
Unaudited pro forma net loss after tax:	'	'	'
Net loss before income tax	'	-16,980,000	'
Pro forma tax provision	'	818,000	'
Pro forma net loss	'	($17,798,000)	'
Class A common stock [Member]	'	'	'
Weighted average number of shares:	'	'	'
Basic and diluted common stock	35,448,056	'	'
Earnings per share for period subsequent to the IPO	'	'	'
Basic and diluted loss per share	($0.17)	'	'
Class B common stock [Member]	'	'	'
Weighted average number of shares:	'	'	'
Basic and diluted common stock	15,555,000	'	'
Earnings per share for period subsequent to the IPO	'	'	'
Basic and diluted loss per share	($0.48)	'	'

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Loss) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Income And Comprehensive Income [Abstract]	'	'	'
Net income (loss)	$10,072	($13,376)	$25,906
Other comprehensive income (loss):	'	'	'
Foreign currency translation, net of tax	-8,309	2,749	-2,406
Effective portion of change in fair market value of derivatives, net of tax	36,875	-11,170	-23,667
Proportionate share of equity investee's other comprehensive income (loss), net of tax	2,473	-1,475	'
Total other comprehensive income (loss), net of tax	31,039	-9,896	-26,073
Comprehensive income (loss)	41,111	-23,272	-167
Less comprehensive income attributable to noncontrolling interest:	'	'	'
Net (loss) income attributable to noncontrolling interest	-6,887	-7,089	16,981
Effective portion of change in fair market value of derivatives, net of tax	5,088	-784	-6,135
Comprehensive (loss) income attributable to noncontrolling interest	-1,799	-7,873	10,846
Comprehensive income (loss)	$42,910	($15,399)	($11,013)

Consolidated_Statement_of_Stoc

Consolidated Statement of Stockholders' Equity (USD $)

Total

Class A common stock [Member]

IPO [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Controlling Interest [Member]

Noncontrolling Interest [Member]

Noncontrolling Interest [Member]

Noncontrolling Interest [Member]

Noncontrolling Interest [Member]

USD ($)

USD ($)

Class A common stock [Member]

USD ($)

Class A common stock [Member]

Class A common stock [Member]

Class A common stock [Member]

Class B common stock [Member]

Additional Paid-in-Capital [Member]

Additional Paid-in-Capital [Member]

Capital [Member]

Accumulated Income (Deficit) [Member]

Accumulated Other Comprehensive Income (Loss) [Member]

Contribution Transactions [Member]

Contribution Transactions [Member]

Contribution Transactions [Member]

Contribution Transactions [Member]

Contribution Transactions [Member]

IPO [Member]

IPO [Member]

IPO [Member]

USD ($)

Capital [Member]

Accumulated Income (Deficit) [Member]

Accumulated Other Comprehensive Income (Loss) [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Class A common stock [Member]

USD ($)

USD ($)

USD ($)

Class A common stock [Member]

Class B common stock [Member]

Additional Paid-in-Capital [Member]

Capital [Member]

Accumulated Income (Deficit) [Member]

Class A common stock [Member]

Class A common stock [Member]

Additional Paid-in-Capital [Member]

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

Class A common stock [Member]

USD ($)

Balance at Dec. 31, 2010

$335,944,000

'

'

$255,160,000

'

'

'

'

'

'

$260,109,000

$265,000

($5,214,000)

'

'

'

'

'

'

'

'

$80,784,000

$82,633,000

$2,474,000

($4,323,000)

Balance, shares at Dec. 31, 2010

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contribution

232,277,000

'

'

232,277,000

'

'

'

'

'

'

232,277,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash distribution

-121,356,000

'

'

-114,198,000

'

'

'

'

'

'

-114,198,000

'

'

'

'

'

'

'

'

'

'

-7,158,000

-7,158,000

'

'

Net income (loss)

25,906,000

'

'

8,925,000

'

'

'

'

'

'

'

8,925,000

'

'

'

'

'

'

'

'

'

16,981,000

'

16,981,000

'

Other comprehensive income (loss), net of tax

-26,073,000

'

'

-19,938,000

'

'

'

'

'

'

'

'

-19,938,000

'

'

'

'

'

'

'

'

-6,135,000

'

'

-6,135,000

Balance at Dec. 31, 2011

446,698,000

'

'

362,226,000

'

'

'

'

'

'

378,188,000

9,190,000

-25,152,000

'

'

'

'

'

'

'

'

84,472,000

75,475,000

19,455,000

-10,458,000

Balance, shares at Dec. 31, 2011

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contribution

281,519,000

'

'

281,519,000

'

'

'

'

'

'

281,519,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash distribution

-115,534,000

'

'

-114,236,000

'

'

'

'

'

'

-114,236,000

'

'

'

'

'

'

'

'

'

'

-1,298,000

-1,298,000

'

'

Issuance of common stock

1,000

'

'

1,000

'

'

'

'

1,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of common stock, shares

'

'

'

'

'

100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income (loss)

-13,376,000

'

'

-6,287,000

'

'

'

'

'

'

'

-6,287,000

'

'

'

'

'

'

'

'

'

-7,089,000

'

-7,089,000

'

Other comprehensive income (loss), net of tax

-9,896,000

'

'

-9,112,000

'

'

'

'

'

'

'

'

-9,112,000

'

'

'

'

'

'

'

'

-784,000

'

'

-784,000

Balance at Dec. 31, 2012

589,412,000

'

'

514,111,000

'

'

'

'

1,000

'

545,471,000

2,903,000

-34,264,000

'

'

'

'

'

'

'

'

75,301,000

74,177,000

12,366,000

-11,242,000

Balance, shares at Dec. 31, 2012

'

'

'

'

'

100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contribution

32,677,000

'

'

32,677,000

'

'

'

'

'

'

32,677,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash distribution

-106,060,000

'

'

-104,634,000

'

'

'

'

'

'

-104,634,000

'

'

'

'

'

'

'

'

'

'

-1,426,000

-1,426,000

'

'

Additional paid-in capital

2,000

'

'

2,000

'

'

'

'

2,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income (loss)

29,605,000

'

'

30,295,000

'

'

'

'

'

'

'

30,295,000

'

'

'

'

'

'

'

'

'

-690,000

'

-690,000

'

Other comprehensive income (loss), net of tax

24,192,000

'

'

20,633,000

'

'

'

'

'

'

'

'

20,633,000

'

'

'

'

'

'

'

'

3,559,000

'

'

3,559,000

Balance at Sep. 30, 2013

569,828,000

'

'

493,084,000

'

'

'

'

3,000

'

473,514,000

33,198,000

-13,631,000

'

'

'

'

'

'

'

'

76,744,000

72,751,000

11,676,000

-7,683,000

Balance, shares at Sep. 30, 2013

'

'

'

'

'

100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at Dec. 31, 2012

589,412,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation

-511,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends declared on Class A common stock

'

-11,103,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income (loss)

10,072,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Other comprehensive income (loss), net of tax

31,039,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at Dec. 31, 2013

568,004,000

'

'

'

'

'

'

156,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance, shares at Dec. 31, 2013

'

'

'

'

'

'

'

15,555,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at Jun. 30, 2013

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Additional paid-in capital

2,000

'

'

'

'

'

'

'

2,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net income (loss)

4,244,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at Sep. 30, 2013

569,828,000

'

'

'

'

'

'

'

3,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance, shares at Sep. 30, 2013

'

'

'

'

'

100

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at Oct. 02, 2013

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest in Gulf Wind retained by Pattern Development

'

'

'

-28,584,000

'

'

'

'

'

'

-18,332,000

-13,122,000

2,870,000

'

'

'

'

'

'

'

'

28,584,000

18,332,000

13,122,000

-2,870,000

Assumption of liabilities related to Contribution Transactions

-4,207,000

'

'

-4,207,000

'

'

'

'

'

'

-4,207,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Cash distribution

-232,640,000

'

'

-232,640,000

'

'

'

'

-232,640,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of Class A restricted common stock

156,000

'

'

156,000

'

1,000

'

'

155,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of common stock

'

93,000

317,042,000

'

93,000

'

'

'

'

93,000

'

'

'

194,000

156,000

470,701,000

-450,975,000

-20,076,000

317,042,000

160,000

316,882,000

'

'

'

'

Issuance of Class A restricted common stock, shares

'

'

'

'

'

83,183

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of common stock, shares

'

'

'

'

'

'

3,437

'

'

'

'

'

'

19,445,000

15,555,000

'

'

'

'

16,000,000

'

'

'

'

'

Repurchase of shares for employee tax withholding

-24,000

'

'

-24,000

'

'

'

'

-24,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Repurchase of shares for employee tax withholding, shares

'

'

'

'

'

-934

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Stock-based compensation

263,000

'

'

263,000

'

'

'

'

263,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends declared on Class A common stock

-11,103,000

'

'

-11,103,000

'

'

'

'

-11,103,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Acquisition from Pattern Development

-57,852,000

'

'

-57,852,000

'

'

'

'

-54,942,000

'

'

'

-2,910,000

'

'

'

'

'

'

'

'

'

'

'

'

Distribution to noncontrolling interest

-866,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-866,000

-866,000

'

'

Net income (loss)

-19,533,000

'

'

-13,336,000

'

'

'

'

'

'

'

-13,336,000

'

'

'

'

'

'

'

'

'

-6,197,000

'

-6,197,000

'

Other comprehensive income (loss), net of tax

6,847,000

'

'

5,318,000

'

'

'

'

'

'

'

'

5,318,000

'

'

'

'

'

'

'

'

1,529,000

'

'

1,529,000

Balance at Dec. 31, 2013

$568,004,000

'

'

$468,210,000

'

$355,000

'

$156,000

$489,388,000

'

'

($13,336,000)

($8,353,000)

'

'

'

'

'

'

'

'

$99,794,000

$90,217,000

$18,601,000

($9,024,000)

Balance, shares at Dec. 31, 2013

'

'

'

'

'

35,530,786

'

15,555,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Statement_of_Cash_Flows

Statement of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating activities	'	'	'
Net income (loss)	$10,072	($13,376)	$25,906
Adjustments to reconcile net income (loss) to net cash provided by operating activities:	'	'	'
Depreciation and accretion	83,180	49,027	39,424
Amortization of financing costs	6,816	2,546	1,477
Unrealized gain (loss) on derivatives	-4,329	11,904	-17,232
Stock-based compensation	511	'	'
Net gain on transactions	-5,995	-4,173	'
Deferred taxes	4,546	-3,604	809
Equity in (earnings) loss in unconsolidated investments	-7,846	40	205
Changes in operating assets and liabilities:	'	'	'
Trade receivables	-8,721	-298	-6,438
Reimbursable interconnection receivable	-11	'	'
Prepaid expenses and other current assets	-2,698	-5,842	2,793
Other assets (non current)	-566	-428	-422
Accounts payable and other accrued liabilities	3,036	-379	167
Income taxes payable	'	'	-259
Related party receivable/payable	190	-100	54
Accrued interest payable	-33	-78	446
Contingent liabilities	'	-188	'
Net cash provided by operating activities	78,152	35,051	46,930
Investing activities	'	'	'
Receipt of ITC Cash Grant	173,446	79,910	'
Payment for acquisition from Pattern Development	-30,070	'	'
Proceeds from sale of investments and tax credits	14,254	4,173	'
Decrease in restricted cash -interconnect and PPA security	66,517	28,431	9,988
Increase in restricted cash -interconnect and PPA security	-80,569	-36,576	-1,889
Capital expenditures	-123,517	-641,422	-392,212
Deferred development costs	-528	-7,093	-17,777
Distribution from unconsolidated investments	10,463	'	'
Contribution to unconsolidated investments	-9,678	-22,387	-13,173
Short-term notes receivable	'	'	80,311
Reimbursable interconnection receivable	49,715	-47,055	'
Other assets (non current)	2,358	3,066	-6,225
Net cash provided by (used in) investing activities	72,391	-638,953	-340,977
Financing activities	'	'	'
Proceeds from IPO, net of expenses	317,926	'	'
Repurchase of shares for employee tax withholding	-24	'	'
Capital distributions-Contribution Transactions	-232,640	'	'
Payment for acquisition from Pattern Development	-49,430	'	'
Capital contributions-controlling interest	32,679	281,519	232,277
Capital distributions	-98,886	-114,236	-114,198
Capital distributions-noncontrolling interest	-2,292	-1,298	-7,158
Decrease in restricted cash-debt service reserves	122,689	26,669	13,048
Increase in restricted cash-debt service reserves	-127,369	-15,850	-14,096
Payment for deferred financing costs	-294	-19,989	-17,001
Proceeds from revolving credit facility	56,000	'	'
Proceeds from long-term debt	138,620	497,226	260,794
Repayment of revolving credit facility	-56,000	'	'
Repayment of long-term debt	-50,324	-27,546	-22,330
Repayment of construction and grant loans	-114,056	-53,328	'
Net cash (used in) provided by financing activities	-63,401	573,167	331,336
Effect of exchange rate changes on cash and cash equivalents	-1,147	637	1,455
Net change in cash and cash equivalents	85,995	-30,098	38,744
Cash and cash equivalents - Beginning of period	17,574	47,672	8,928
Cash and cash equivalents - End of period	103,569	17,574	47,672
Supplemental disclosure	'	'	'
Cash payments for interest and commitment fees	57,505	43,474	30,648
Cash payments for income taxes	'	'	141
Schedule of non-cash activities	'	'	'
Change in fair value of interest rate swaps	52,244	-11,173	-23,667
Change in fair value of contingent liabilities	'	-2,015	-486
Amortization of deferred financing costs-included as construction in progress	175	3,824	595
Capitalized interest	4,171	9,386	3,621
Capitalized commitment fee	39	873	599
Change in property, plant and equipment	-192,461	30,154	-61,338
Transfer of capitalized assets to South Kent joint venture	49,275	'	'
Non-cash distribution to Pattern Development	-5,748	'	'
Assumption of liabilities related to Contribution Transactions	-4,207	'	'
Accrued IPO stock issuance costs	($884)	'	'

Organization

Organization	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Organization	'
	1	Organization
	Pattern Energy Group Inc. (“Pattern Energy” or the “Company”) was organized in the state of Delaware on October 2, 2012. Pattern Energy issued 100 shares on October 17, 2012 to Pattern Renewables LP, a 100% owned subsidiary of Pattern Energy Group LP (“Pattern Development”). On September 24, 2013, Pattern Energy’s charter was amended, and the number of shares that Pattern Energy is authorized to issue was increased to 620,000,000 total shares; 500,000,000 of which are designated Class A Common Stock, 20,000,000 of which are designated Class B Common Stock, and 100,000,000 of which are designated Preferred Stock.
	Pattern Energy is an independent energy generation company focused on constructing, owning and operating energy projects with long-term energy sales contracts located in the United States, Canada and Chile. The Company consists of the consolidated operations of certain entities and assets contributed by Pattern Development. The Company owns 100% of Hatchet Ridge Wind, LLC (Hatchet Ridge), St. Joseph Windfarm Inc. (St. Joseph), Spring Valley Wind LLC (Spring Valley), Pattern Santa Isabel LLC (Santa Isabel) and Ocotillo Express LLC (Ocotillo). The Company owns a controlling interest in Pattern Gulf Wind Holdings LLC (Gulf Wind) and noncontrolling interests in South Kent Wind LP (South Kent), Grand Renewable Wind LP (Grand) and AEI-Pattern Holding Limitada (El Arrayán). The principal business objective of the Company is to produce stable and sustainable cash flows through the generation and sale of energy.
	Initial Public Offering and Contribution Transactions
	On October 2, 2013, Pattern Energy issued 16,000,000 shares of Class A common stock in an initial public offering (“IPO”) generating net proceeds of approximately $317.0 million. Concurrent with the IPO, Pattern Energy issued 19,445,000 shares of Class A common stock and 15,555,000 shares of Class B common stock to Pattern Development and utilized approximately $232.6 million of the net proceeds of the IPO as a portion of the consideration to Pattern Development for certain entities and assets contributed to Pattern Energy (“Contribution Transactions”) consisting of interests in eight wind power projects, including six projects in operation (Gulf Wind, Hatchet Ridge, St. Joseph, Spring Valley, Santa Isabel and Ocotillo), and two projects under construction (El Arrayán and South Kent). In accordance with ASC 805-50-30-5, Transactions between Entities under Common Control, Pattern Energy recognized the assets and liabilities contributed by Pattern Development at their historical carrying amounts at the date of the Contribution Transactions. On October 8, 2013, Pattern Energy’s underwriters exercised in full their overallotment option to purchase 2,400,000 shares of Class A common stock from Pattern Development, the selling stockholder, pursuant to the overallotment option granted by Pattern Development.
	In connection with the Contribution Transactions, Pattern Development retained a 40% portion of the interest in Gulf Wind previously held by it such that, at the completion of the IPO, Pattern Energy, Pattern Development and the joint venture partner held interests of approximately 40%, 27% and 33%, respectively, of the distributable cash flow of Gulf Wind, together with certain allocated tax items.
	Effective with Pattern Energy’s IPO, Pattern Development’s project operations and maintenance personnel and certain of its executive officers became Pattern Energy employees and their employment with Pattern Development was terminated. Pattern Development retained those employees whose primary responsibilities relate to project development, legal, financial or other administrative functions. Pattern Energy entered into a bilateral services agreement with Pattern Development, or the “Management Services Agreement”, that provides for Pattern Energy and Pattern Development to benefit, primarily on a cost-reimbursement basis, from the respective management and other professional, technical and administrative personnel of the respective companies, all of whom report to and are managed by Pattern Energy’s executive officers.
	Basis of Presentation
	Pattern Energy was formed by Pattern Development for the purpose of an IPO and does not have any historical financial operating results. For periods prior to October 2, 2013, Pattern Energy was a shell company, with expenses of less than $10,000 for 2013 and 2012. In accordance with ASC 805-50-30-6, the historical financial statements of Pattern Energy’s predecessor, which consist of the combined financial statements of a combination of entities and assets contributed by Pattern Development to Pattern Energy, are consolidated with Pattern Energy (the “Company”) from the beginning of the earliest period presented.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	2	Summary of Significant Accounting Policies
	Principles of Consolidation
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). They include the results of wholly-owned and partially-owned subsidiaries in which the Company has a controlling interest with all significant intercompany accounts and transactions eliminated.
	Use of Estimates
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates, and such differences may be material to the consolidated financial statements.
	Unaudited Pro Forma Income Tax
	In order to present the tax effect of the Contribution Transactions, the Company has presented a 2012 pro forma income tax provision as if the Contribution Transactions occurred effective January 1, 2012 and as if the Company were under control of a Subchapter C-Corporation for U.S. federal income tax purposes.
	Variable Interest Entities
	ASC 810, Consolidation of Variable Interest Entities, defines the criteria for determining the existence of Variable Interest Entities (VIEs) and provides guidance for consolidation. The Company consolidates VIEs where the Company is the primary beneficiary. The primary beneficiary of a VIE is the party that has the power to direct the activities that most significantly impact the performance of the entity and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the entity.
	Investments or joint ventures in which the Company does not have a majority ownership interest and are not VIEs for which the Company is considered the primary beneficiary are accounted for using the equity method. These amounts are included in unconsolidated investments in the consolidated balance sheets.
	Noncontrolling Interests
	Noncontrolling interests represent third-party interests in Gulf Wind which resulted from the sale of a noncontrolling interest to an unrelated third party on September 3, 2010 and the interest retained by Pattern Development in connection with the Contribution Transactions on October 2, 2013. The Company has determined that the operating partnership agreement for Gulf Wind does not allocate economic benefits pro rata to its two classes of investors and the appropriate methodology for calculating the noncontrolling interest balance that reflects the substantive profit sharing arrangement is a balance sheet approach using the hypothetical liquidation at book value (HLBV) method.
	Under the HLBV method, the amounts reported as noncontrolling interest in the consolidated balance sheets and consolidated statements of operations represent the amounts the third party would hypothetically receive at each balance sheet reporting date under the liquidation provisions of the operating partnership agreement assuming the net assets of Gulf Wind were liquidated at recorded amounts determined in accordance with U.S. GAAP and distributed to the investors. The third-party interest in the results of operations of Gulf Wind and the Company’s net income and comprehensive income is determined as the difference in noncontrolling interests in the consolidated balance sheets at the start and end of each reporting period, after taking into account any capital transactions between Gulf Wind and the third party. The noncontrolling interest balance in Gulf Wind is reported as a component of equity in the consolidated balance sheets.
	Foreign Currency Translation
	The assets and liabilities of foreign subsidiaries, where the local currency is the functional currency, are translated from their respective functional currencies into U.S. dollars at the rates in effect at the balance sheet date, with resulting foreign currency translation adjustments recorded in other comprehensive income (loss), net of tax in the accompanying consolidated statements of stockholders’ equity and comprehensive income (loss). Revenue and expense amounts are translated at average rates during the period. Where the U.S. dollar is the functional currency, translation adjustments are recorded in other income, net in the accompanying consolidated statements of operations.
	Gains and losses realized from transactions, including related party balances not considered permanent investments, denominated in currencies other than an entity’s functional currency are included in other income, net in the accompanying consolidated statements of operations.
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, trade receivables and derivative assets. The Company places its cash and cash equivalents with high quality institutions.
	The Company sells electricity and environmental attributes, including renewable energy credits, primarily to creditworthy utilities under long-term, fixed-priced PPAs. The table below presents significant customers who accounted for the following percentages of total revenues:
		Year ended December 31,
		2013			2012			2011
	Manitoba Hydro		17.62	%		32.06	%		20.91	%
	San Diego Gas & Electric		17.23	%		0.18	%		0	%
	Pacific Gas & Electric Company		14.54	%		23.12	%		20.67	%
	Electric Reliability Council of Texas		12.24	%		18.28	%		35.23	%
	The Company’s derivative assets are placed with counterparties that are creditworthy institutions. A derivative asset was generated from Credit Suisse Energy LLC, the counterparty to a 10-year fixed-for-floating swap related to annual electricity generation at the Company’s Gulf Wind project. The Company’s reimbursements for prepaid interconnect network upgrades are with large creditworthy utility companies.
	Fair Value of Financial Instruments
	ASC 820, Fair Value Measurements, defines fair value as the price at which an asset could be exchanged or a liability transferred in an orderly transaction between knowledgeable, willing parties in the principal or most advantageous market for the asset or liability. Where available, fair value is based on observable market prices or derived from such prices. Where observable prices or inputs are not available, valuation models are applied. These valuation techniques involve some level of management estimation and judgment, the degree of which is dependent on the price transparency for the instruments or market and the instruments’ complexity. See Note 12 on Fair Value Measurements.
	U.S. Treasury Grants
	The Company received U.S. Treasury grants on certain wind power projects as defined under Section 1603 of the American Recovery and Reinvestment Act of 2009, as amended by the Tax Relief Unemployment Insurance Reauthorization and Job Creation Act of December 2010, upon approval by the U.S. Treasury Department. The Company records the U.S. Treasury grant proceeds as a deduction from the carrying amount of the related asset which results in a reduction of depreciation expense over the life of the asset. The Company records a catch-up adjustment in the period in which the grant is approved to recognize the portion of the grant that proportionally matches the depreciation for the period between the date of placement in service of the wind power project and approval by the U.S. Treasury Department. See Note 5 on Property, Plant and Equipment.
	Cash and Cash Equivalents
	Cash and cash equivalents consist of all cash balances and highly-liquid investments with original maturities of three months or less. The Company maintains cash and cash equivalents, which consist principally of demand deposits with high credit quality financial institutions. The Company has exposure to credit risk to the extent cash and cash equivalent balances, including restricted cash, exceed amounts covered by federal deposit insurance. The Company believes that its credit risk is immaterial.
	Restricted Cash
	Restricted cash consists of cash balances which are restricted as to withdrawal or usage and include cash to collateralize bank letters of credit related primarily to interconnection rights and power purchase agreements (“PPAs”) and for certain reserves required under the Company’s loan agreements.
	Trade Receivables
	The Company’s trade receivables are generated by selling energy and renewable energy credits in the California, Texas, Nevada, Manitoba (Canada) and Puerto Rico energy markets. The Company believes that all amounts are collectible and an allowance for doubtful accounts is not required as of December 31, 2013 and 2012.
	Reimbursable Interconnect Costs
	During 2013 and 2012, the Company paid to construct interconnect network upgrades for one of its utility customers. The utility owns the interconnect upgrades and reimbursed the Company with interest when the project reached commercial operations in 2013.
	Turbine Advances
	Turbine advances represent amounts advanced to turbine suppliers for the manufacture of wind turbines in accordance with turbine supply agreements for the Company’s wind power projects and for which the Company has not taken title. Turbine advances are reclassified to construction in progress when the Company takes legal title to the related turbines and are reclassified to property, plant and equipment when the project achieves commercial operation. Depreciation does not commence until projects enter commercial operation and assets are placed in service.
	Deferred Development Costs
	Deferred development costs consist primarily of initial permitting, environmental reviews, land rights and obligations and preliminary design and engineering work. The Company expenses all project development costs until a project is determined to be technically feasible and likely to achieve commercial success. Capitalized deferred project development costs are reclassified to construction in progress upon start of construction and recorded to property, plant and equipment upon commercial operation.
	Construction in Progress
	Construction in progress represents the accumulated costs of projects in construction. Construction costs include turbines for which the Company has taken legal title, civil engineering, electrical and other related costs. Other capitalized costs include reclassified deferred development costs, amortization of intangible assets, amortization of deferred financing costs, capitalized interest and other costs required to place a project into commercial operation. Construction in progress is reclassified to property, plant and equipment when the project begins commercial operation.
	Property, Plant and Equipment
	Property, plant and equipment represents the costs of completed and operational projects transferred from construction in progress as well as land, computer equipment and software, furniture and fixtures, leasehold improvements and other equipment. Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the assets’ useful lives. Wind farms are depreciated over twenty years and the remaining assets are depreciated over three to five years. Land is not depreciated. Improvements to property, plant and equipment deemed to extend the useful economic life of an asset are capitalized. Repair and maintenance costs are expensed as incurred.
	Accounting for Impairment of Long-Lived Assets
	The Company periodically evaluates whether events have occurred that would require revision of the remaining useful life of equipment and improvements and purchased intangible assets or render them not recoverable. If such circumstances arise, the Company uses an estimate of the undiscounted value of expected future operating cash flows to determine whether the long-lived assets are impaired. If the aggregate undiscounted cash flows are less than the carrying amount of the assets, the resulting impairment charge to be recorded is calculated based on the excess of the carrying value of the assets over the fair value of such assets, with the fair value determined based on an estimate of discounted future cash flows. Through December 31, 2013, no impairment charges have been recorded.
	Derivatives
	The Company recognizes its derivative instruments as assets or liabilities at fair value in the consolidated balance sheets. Accounting for changes in the fair value (i.e., gains or losses) of a derivative instrument depends on whether it has been designated as part of a hedging relationship and on the type of hedging relationship.
	For derivative instruments that are designated as cash flow hedges the effective portion of change in fair value of the derivative is reported as a component of other comprehensive income (loss) (“OCI”). Changes in the fair value of these derivatives are subsequently reclassified into earnings in the period that the hedged transaction affects earnings. The ineffective portion of change in fair value is recorded as a component of net income (loss) on the consolidated statement of operations.
	For undesignated derivative instruments their change in fair value is reported as a component of net income on the consolidated statement of operations.
	The Company enters into derivative transactions for the purpose of reducing exposure to fluctuations in interest rates and electricity prices. The Company has entered into interest rate swaps, an interest rate cap and an electricity price derivative.
	Interest rate swaps are instruments used to fix the interest rate on variable interest rate debt. The Company entered into interest rate swaps in 2013, 2012 and 2011.
	An interest rate cap is an instrument that is used to reduce exposure to future variable interest rates when the related debt is expected to be refinanced. The Company entered into an interest rate cap in 2010. The cap remains in place as of December 31, 2013.
	The Company entered into an electricity price arrangement, which qualifies as a derivative, that fixes the price of approximately 58% of the electricity expected to be produced and sold by Gulf Wind through April 2019, and which reduces the Company’s exposure to spot electricity prices.
	Deferred Financing Costs
	Financing costs incurred in connection with obtaining construction and term financing are deferred and amortized over the lives of the respective loans using the effective-interest method. Amortization of deferred financing costs is capitalized during construction and recorded as interest expense in the consolidated statements of operations following commencement of commercial operation.
	Income Taxes
	Prior to October 2, 2013, the Company’s predecessor did not provide for income taxes as it was treated as a pass-through entity for U.S. federal and state income tax purposes, except for several specific circumstances involving its Canadian entities, which are subject to Canadian income taxes, its Chilean entities, which are subject to Chilean income taxes, a U.S. entity that is subject to Puerto Rican taxes and a U.S. entity which became subject to U.S. income taxes in 2012. Federal and state income taxes were assessed at the owner level and each owner was liable for its own tax payments. Certain consolidated entities are corporations or have elected to be taxed as corporations. In these circumstances, income tax was accounted for under the asset and liability method.
	Subsequent to October 2, 2013, following the Contribution Transactions, the Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, it would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions in accordance with ASC 740 on the basis of a two-step process whereby (1) it determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, it recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company has a policy to classify interest and penalties associated with uncertain tax positions together with the related liability, and the expenses incurred related to such accruals, if any, are included in the provision for income taxes.
	Contingent Liabilities
	The Company’s contingent liabilities represent deferred and contingent purchase price obligations related to projects acquired through business combinations and are recorded at fair value at each reporting date.
Asset Retirement Obligation
The Company records asset retirement obligations for the estimated costs of decommissioning turbines, removing above-ground installations and restoring sites, at the time when a contractual decommissioning obligation materializes. The Company records accretion expense, which represents the increase in the asset retirement obligations, over the remaining or operational life of the associated wind project. Accretion expense is recorded as cost of revenue in the statement of operations using accretion rates based on credit adjusted risk free interest rates.
Revenue Recognition
The Company sells the electricity it generates under the terms of PPAs or at spot market prices. Revenue is recognized based upon the amount of electricity delivered at rates specified under the contracts, assuming all other revenue recognition criteria are met. The Company evaluates its PPAs to determine whether they are in substance leases or derivatives and, if applicable, recognizes revenue pursuant to ASC 840 Leases and ASC 815 Derivatives and Hedging, respectively. As of December 31, 2013, there were no PPAs that are accounted for as leases or derivatives and revenue is recognized on an accrual basis.
The Company also generates renewable energy credits as it produces electricity. Certain of these energy credits are sold independently in an open market and revenue is recognized at the time title to the energy credits is transferred to the buyer.
The Company acquired a ten-year energy derivative instrument as part of its acquisition of Gulf Wind in 2010, which fixes approximately 58% of the Project’s expected electricity generation through April 2019. The energy derivative instrument reduces exposure to changes in commodity prices by allowing the Company to lock in a fixed price per MWh for a specified amount of annual electricity generation. The monthly settlement amounts under the energy hedge are accounted for as energy derivative settlements in the consolidated statements of operations. The change in the fair value of the energy hedge is classified as unrealized (loss) gain on energy derivative revenue in the consolidated statements of operations.
The Company recognizes revenue for warranty settlements and liquidated damages from turbine manufacturers in other revenue upon resolution of outstanding contingencies. Any cash receipts for amounts subject to future adjustment or repayment are deferred in other liabilities until the final settlement amount is considered fixed and determinable.
Cost of Revenue
The Company’s cost of revenue is comprised of direct costs of operating and maintaining its wind project facilities, including labor, turbine service arrangements, land lease royalties, depreciation, accretion, property taxes and insurance.
Stock-Based Compensation
The Company accounts for stock-based compensation related to stock options granted to employees by estimating the fair value of the stock-based awards using the Black-Scholes option-pricing model. The fair value of the stock options granted are amortized over the applicable vesting period. The Black-Scholes option pricing model includes assumptions regarding dividend yields, expected volatility, expected option term, expected forfeiture rate and risk-free interest rates. The Company estimates expected volatility based on the historical volatility of comparable publicly traded companies for a period that is equal to the expected term of the options. The risk-free interest rate is based on the U.S. treasury yield curve in effect at the time of grant for a period commensurate with the estimated expected life. The expected term of options granted is derived using the “simplified” method as allowed under the provisions of the ASC 718, Compensation—Stock Compensation, and represents the period of time that options granted are expected to be outstanding.
The Company accounts for stock-based compensation related to restricted stock award grants by amortizing the fair value of the restricted stock award grants, which is the grant date market price, over the applicable vesting period.
Stock-based compensation expense is recorded as a component of general and administrative expenses in the Company’s consolidated statements of operations.
Comprehensive Income (Loss)
Comprehensive income (loss) consists of net income (loss) and other comprehensive income (loss), net of tax. Other comprehensive income (loss), net of tax included in accumulated other comprehensive income (loss) in the accompanying consolidated statements of stockholders’ equity, is comprised of changes in foreign currency translation adjustments and changes in the fair value of derivatives designated as hedges.
Segment Data
Operating segments are defined as components of a company about which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the chief executive officer. Based on the financial information presented to and reviewed by the chief operating decision maker in deciding how to allocate the resources and in assessing the Company’s performance, the Company has determined its wind projects represent individual operating segments with similar economic characteristics that meet the criteria for aggregation into a single reporting segment for financial statement purposes.

Acquisition_from_Pattern_Devel

Acquisition from Pattern Development	12 Months Ended
	Dec. 31, 2013
Business Combinations [Abstract]	'
Acquisition from Pattern Development	'
	3	Acquisition from Pattern Development
	On December 20, 2013, the Company acquired from Pattern Development a 45% equity interest in Grand for $79.5 million, paid in 2013, plus a contingent payment of up to $4.7 million, payable in 2014. Grand is a joint venture established to develop, construct, and own a wind power project located in Ontario, Canada. The project has a 20-year PPA and commenced construction in September 2013. The Company’s investment in Grand was paid from general corporate funds. Grand is accounted for under the equity method of accounting. In accordance with ASC 805-50-30-5, Transactions between Entities under Common Control, the Company recognized the investment at the historical carrying amount at the date of acquisition.

Prepaid_Expenses_and_Other_Cur

Prepaid Expenses and Other Current Assets	12 Months Ended
	Dec. 31, 2013
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]	'
Prepaid Expenses and Other Current Assets	'
	4	Prepaid expenses and other current assets
	The following table presents the components of prepaid expenses and other current assets (in thousands):
		December 31,
		2013		2012
	Prepaid expenses	$	10,132	$	7,202
	Sales tax		50		3,275
	Interconnection network upgrade receivable		2,512		1,854
	Other current assets		1,233		1,463
	Prepaid expenses and other current assets	$	13,927	$	13,794

Property_Plant_and_Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2013
Property Plant And Equipment [Abstract]	'
Property, Plant and Equipment	'
	5	Property, Plant and Equipment
	The following presents the categories within property, plant and equipment (in thousands):
		December 31,
		2013			2012
	Operating wind farms	$	1,652,119		$	1,765,200
	Furniture, fixtures and equipment		3,785			3,333
	Land		16			16
	Subtotal		1,655,920			1,768,549
	Less: accumulated depreciation		(179,778	)		(100,247	)
		$	1,476,142		$	1,668,302
	The Company recorded depreciation expense related to property, plant and equipment of $82.0 million, $48.3 million and $38.9 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	In June 2013, the Company received $115.9 million and $57.6 million for Ocotillo and Santa Isabel, respectively, under a cash grant in lieu of investment tax credit (Cash Grant) from the U.S. Department of the Treasury. In December 2012, the Company received $79.9 million for Spring Valley under a Cash Grant from the U.S. Department of the Treasury. The Company recorded the cash proceeds as a deduction from the carrying amount of the related wind farm assets which resulted in the assets being recorded at lower amounts.
	The Cash Grants received for Ocotillo, Santa Isabel, and Spring Valley reduced depreciation expense recorded in the consolidated statements of operations by approximately $13.0 million and $1.5 million for the years ended December 31, 2013 and 2012, respectively.

Unconsolidated_Investments

Unconsolidated Investments	12 Months Ended
	Dec. 31, 2013
Equity Method Investments And Joint Ventures [Abstract]	'
Unconsolidated Investments	'
	6	Unconsolidated Investments
	The following presents projects that are accounted for under the equity method of accounting (in thousands):
							Percentage of Ownership
		December 31,					December 31,
		2013			2012		2013			2012
	South Kent	$	59,488		$	17,895		50	%		50	%
	El Arrayán		21,103			18,323		31.5	%		31.5	%
	Grand		26,464			—		45	%		N/A
	Unconsolidated investments	$	107,055		$	36,218
	South Kent
	The Company is a noncontrolling investor in a joint venture established to develop, construct, and own a wind power project located in Ontario, Canada. The project has a 20-year PPA. Construction commenced in March 2013.
	El Arrayán
	The Company is a noncontrolling investor in a joint venture established to develop, construct, and own a wind power project located in Chile. The project has a 20-year PPA and commenced construction in May 2012.
	Grand
	On December 20, 2013, the Company acquired from Pattern Development a 45% equity interest in Grand for $79.5 million, paid in 2013, plus a contingent payment of up to $4.7 million, payable in 2014. Grand is a joint venture established to develop, construct, and own a wind power project located in Ontario, Canada. The project has a 20-year PPA and commenced construction in September 2013. The Company’s investment in Grand was paid from general corporate funds. The Company is a noncontrolling investor in Grand and the investment is accounted for under the equity method of accounting.
	The following summarizes the aggregated balance sheets as of December 31, 2013 and 2012, and operating results of the unconsolidated joint ventures for the years ended December 31, 2013, 2012 and 2011, respectively (in thousands):
		December 31,
		2013			2012
	Current assets	$	78,906		$	33,578
	Non-current assets		1,097,018			142,522
	Total assets	$	1,175,924		$	176,100
	Current liabilities	$	128,076		$	5,153
	Non-current liabilities		810,936			71,709
	Total liabilities	$	939,012		$	76,862
	Total equity	$	236,912		$	99,238
	Total liabilities and equity	$	1,175,924		$	176,100
		Year ended December 31,
		2013			2012		2011
	Revenue	$	—		$	—	$	—
	Other (income) expense		(13,322	)		275		455
	Net income (loss)	$	13,322			$  (275)		$  (455)
	6	Unconsolidated Investments
	The following presents projects that are accounted for under the equity method of accounting (in thousands):
							Percentage of Ownership
		December 31,					December 31,
		2013			2012		2013			2012
	South Kent	$	59,488		$	17,895		50	%		50	%
	El Arrayán		21,103			18,323		31.5	%		31.5	%
	Grand		26,464			—		45	%		N/A
	Unconsolidated investments	$	107,055		$	36,218
	South Kent
	The Company is a noncontrolling investor in a joint venture established to develop, construct, and own a wind power project located in Ontario, Canada. The project has a 20-year PPA. Construction commenced in March 2013.
	El Arrayán
	The Company is a noncontrolling investor in a joint venture established to develop, construct, and own a wind power project located in Chile. The project has a 20-year PPA and commenced construction in May 2012.
	Grand
	On December 20, 2013, the Company acquired from Pattern Development a 45% equity interest in Grand for $79.5 million, paid in 2013, plus a contingent payment of up to $4.7 million, payable in 2014. Grand is a joint venture established to develop, construct, and own a wind power project located in Ontario, Canada. The project has a 20-year PPA and commenced construction in September 2013. The Company’s investment in Grand was paid from general corporate funds. The Company is a noncontrolling investor in Grand and the investment is accounted for under the equity method of accounting.
	The following summarizes the aggregated balance sheets as of December 31, 2013 and 2012, and operating results of the unconsolidated joint ventures for the years ended December 31, 2013, 2012 and 2011, respectively (in thousands):
		December 31,
		2013			2012
	Current assets	$	78,906		$	33,578
	Non-current assets		1,097,018			142,522
	Total assets	$	1,175,924		$	176,100
	Current liabilities	$	128,076		$	5,153
	Non-current liabilities		810,936			71,709
	Total liabilities	$	939,012		$	76,862
	Total equity	$	236,912		$	99,238
	Total liabilities and equity	$	1,175,924		$	176,100
		Year ended December 31,
		2013			2012		2011
	Revenue	$	—		$	—	$	—
	Other (income) expense		(13,322	)		275		455
	Net income (loss)	$	13,322			$  (275)		$  (455)

Accounts_Payable_and_Other_Acc

Accounts Payable and Other Accrued Liabilities	12 Months Ended
	Dec. 31, 2013
Payables And Accruals [Abstract]	'
Accounts Payable and Other Accrued Liabilities	'
	7	Accounts payable and other accrued liabilities
	The following table presents the components of accounts payable and other accrued liabilities (in thousands):
		December 31,
		2013		2012
	Accounts payable	$	168	$	331
	Other accrued liabilities		7,282		3,847
	Warranty settlement payments		2,187		—
	Payroll liabilities		2,162		—
	Property tax payable		3,490		3,444
	Sales tax payable		261		128
	Accounts payable and other accrued liabilities	$	15,550	$	7,750

Long_term_debt

Long term debt	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Long term debt	'
	8	Long term debt
	The Company’s long term debt as of December 31, 2013 and 2012 is presented below (in thousands):
		December 31,						Interest Rate as of						Interest
								December 31,						Type
		2013			2012			2013			2012				Maturity
	Santa Isabel bridge loan	$	—		$	38,337			N/A			2.31	%	Variable	N/A
	Ocotillo bridge loan		—			56,586			N/A			3.31	%	Variable	N/A
	Hatchet Ridge term loan		239,865			251,119			1.43	%		1.43	%	Imputed	December 2032
	Gulf Wind term loan		166,448			174,969			3.25	%		3.36	%	Variable	Mar-20
	St. Joseph term loan		215,330			238,737			5.88	%		5.88	%	Fixed	May-31
	Spring Valley term loan		173,110			178,900			2.63	%		2.62	%	Variable	Jun-30
	Santa Isabel term loan		115,721			119,035			4.57	%		4.57	%	Fixed	September 2033
	Ocotillo commercial term loan		230,944			160,299			3	%		3.31	%	Variable	Aug-20
	Ocotillo development term loan		107,800			72,588			2.35	%		2.41	%	Variable	Aug-33
			1,249,218			1,290,570
	Less: current portion		(48,851	)		(137,258	)
		$	1,200,367		$	1,153,312
	The following are amounts due for long-term debt as of December 31, 2013 (in thousands):
	For the year ending December 31,
	2014	$	48,851
	2015		58,888
	2016		60,442
	2017		61,571
	2018		66,547
	Thereafter		952,919
		$	1,249,218
	Interest and commitment fees incurred, and interest expense recorded in the Company’s consolidated statements of operations are as follows (in thousands):
		Year ended December 31,
		2013			2012			2011
	Interest and commitment fees incurred	$	57,478		$	43,496		$	31,610
	Capitalized interest, commitment fees, and letter of credit fees		(4,210	)		(10,259	)		(4,220	)
	Letter of credit fees		3,530			720			537
	Amortization of financing costs		6,816			2,545			1,477
	Interest expense	$	63,614		$	36,502		$	29,404
	Hatchet Ridge
	In December 2010, Hatchet Ridge entered into sale-leaseback transactions to finance the facility for 22 years. In accordance with ASC 840, Leases, Hatchet Ridge accounts for the sale-leaseback as a financing transaction.
	Collateral for the sale-leaseback financing includes Hatchet Ridge’s tangible assets and contractual rights and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict Hatchet Ridge’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.
	Gulf Wind
	The Company acquired Gulf Wind in March 2010. Concurrent with its acquisition, Gulf Wind entered into a $195.4 million credit facility. The Gulf Wind credit facility has a term of ten years. In connection with the facility, Gulf Wind entered into interest rate swaps and cap agreements to reduce its exposure to variable interest rates of the term of the facility and to hedge its exposure to re-financing rate risk.
	Collateral for the Gulf Wind credit facility includes Gulf Wind’s tangible assets and contractual rights and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict Gulf Wind’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.
	St. Joseph
	In March 2010, St. Joseph entered into a $259.5 million construction and term loan facility that was converted to a 20-year term loan in May 2011.
	Collateral for the St. Joseph facility includes St. Joseph’s tangible assets and contractual rights and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict St. Joseph’s ability to incur debt, grant liens, sell or lease certain assets, transfer equity interests, dissolve, make distributions and change its business.
	Spring Valley
	In August 2011, Spring Valley entered into a $178.9 million construction loan facility and a $53.3 million cash grant bridge loan. Spring Valley reached commercial operations on August 16, 2012 and the construction loan was converted to a term loan on November 16, 2012. The cash grant bridge loan was repaid in December 2012 from funds the Company received under a Cash Grant from the U.S. Department of Treasury following the wind project being placed in service. In connection with the term loan, Spring Valley entered into interest rate swaps for the term of the loan to hedge its exposure to variable interest rates following term conversion of the facility.
	Collateral for the loan consists of Spring Valley’s tangible assets and contractual rights, and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict Spring Valley’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.
	Santa Isabel
	In October 2011, Santa Isabel entered into a $119.0 million construction loan facility and a $57.5 million cash grant bridge loan facility. On December 5, 2012, Santa Isabel achieved commercial operations under the terms of its PPA. The construction loan converted to a term loan on May 15, 2013 and matures on September 30, 2033. The cash grant bridge loan was repaid from funds the Company received under a Cash Grant in May 2013.
	Collateral for the Santa Isabel facility consists of Santa Isabel’s tangible assets and contractual rights, and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict Santa Isabel’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.
	Ocotillo
	In October 2012, Ocotillo entered into a $467.3 million financing agreement comprised of two construction loan facilities totaling $351.5 million, a network upgrade bridge loan facility of $56.6 million and a letter of credit facility of $59.2 million. The two loan facilities consist of a development bank tranche of $110.0 million and a commercial bank tranche of $241.5 million. Ocotillo reached full commercial operations in July 2013, and the two construction loans converted to term loans on September 20, 2013 and mature 20 years and 7 years after the term loan conversion, respectively. The network upgrade bridge loan was repaid in August 2013 from reimbursements received from the utility related to the construction of network upgrade costs. In connection with the financing agreement, the Company entered into interest rate swaps on 90% of the loan commitment. In addition, in September 2013, Ocotillo prepaid $2.2 million of the development bank loan and $5.3 million of the commercial bank loan pursuant to a proposal initiated by Ocotillo and accepted by the lenders.
	Collateral under the Ocotillo financing agreement consists of Ocotillo’s tangible assets and contractual rights, and cash on deposit with the depository agent. Its loan agreement contains a broad range of covenants that, subject to certain exceptions, restrict Ocotillo’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.
	Revolving Credit Facility
	On November 15, 2012, the Company entered into a $120.0 million revolving credit agreement for working capital with a four-year term comprised of a revolving loan facility and a letter of credit facility. The revolving credit agreement has an “accordion feature” under which the Company has the right to increase available borrowings by up to $35.0 million if its lenders or other additional lenders are willing to lend on the same terms and meet certain other conditions. As of December 31, 2013 and 2012, letters of credit of $44.8 million and $39.1 million, respectively, have been issued and loans of $56.0 million and zero were drawn and repaid in 2013 and 2012, respectively. As of December 31, 2013 and 2012, there was no outstanding balance on the revolving credit facility.
	Loans, when and if drawn, are either base rate loans or Eurodollar rate loans. The base rate loans accrue interest at 2.5% plus the greatest of the (i) the prime rate, (ii) the federal funds rate plus 0.5% and (iii) the Eurodollar rate that would be in effect for a Eurodollar rate loan with an interest period of one month plus 1.0%. The Eurodollar rate loans will accrue interest at a rate per annum equal to LIBOR, as published by Reuters plus 3.5%. Collateral for the revolving credit facility consists of the Company’s membership interests in certain of the Company’s holding company subsidiaries. The revolving credit facility contains a broad range of covenants that, subject to certain exceptions, restrict the Company’s ability to incur debt, grant liens, sell or lease assets, transfer equity interests, dissolve, pay distributions and change its business.

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation Disclosure [Abstract]	'
Asset Retirement Obligations	'
	9	Asset Retirement Obligations
	The Company’s asset retirement obligations represent the estimated cost of decommissioning the turbines, removing above-ground installations and restoring the sites at a date that is 20 years from the commencement of commercial operation of the facility.
	The following table presents a reconciliation of the beginning and ending aggregate carrying amounts of asset retirement obligations as of December 31, 2013, 2012 and 2011 (in thousands):
		December 31,
		2013			2012		2011
	Beginning asset retirement obligations	$	19,056		$	10,342	$	9,365
	Additions during the year		767			7,971		467
	Foreign currency translation adjustment		(172	)		59		(43	)
	Accretion expense		1,183			684		553
	Ending asset retirement obligations	$	20,834		$	19,056	$	10,342

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Instruments	'
	10	Derivative Instruments
	The Company employs a variety of derivative instruments to manage its exposure to fluctuations in interest rates and electricity prices. The following tables present the amounts that are recorded in the Company’s consolidated balance sheets as of December 31, 2013, 2012 and 2011 (in thousands):
	Undesignated Derivative Instruments Classified as Assets (Liabilities):
				As of						Year ended
				Fair Market Value						YTD Gain (Loss)
	Derivative Type	Quantity	Maturity	Current			Long-Term			Recognized into
			Dates	Portion			Portion			Income
	December 31, 2013
	Interest rate swaps	6	6/30/30	$	(3,899	)	$	14,358		$	15,367
	Interest rate cap	1	12/31/24		—			681			234
	Energy derivative	1	4/30/19		13,937			54,416			(11,272	)
				$	10,038		$	69,455		$	4,329
	December 31, 2012
	Interest rate swaps	6	6/30/30	$	(1,980	)	$	(2,931	)	$	(4,909	)
	Interest rate cap	1	12/31/24		—			447			(44	)
	Energy derivative	1	4/30/19		17,177			62,448			(6,951	)
				$	15,197		$	59,964		$	(11,904	)
	December 31, 2011
	Interest rate cap	1	12/31/24	$	—		$	491		$	(345	)
	Energy derivative	1	4/30/19		18,687			67,890			17,577
				$	18,687		$	68,381		$	17,232
	Designated Derivative Instruments Classified as Assets ( Liabilities):
				As of						Year ended
				Fair Market Value						YTD Gain (Loss)
	Derivative Type	Quantity	Maturity	Current			Long-Term			Recognized in
			Dates	Portion			Portion			OCI
	December 31, 2013
	Interest rate swaps	6	6/30/33	$	(2,105	)	$	9,625		$	10,434
	Interest rate swaps	7	3/15/20		(5,289	)		(7,439	)		9,398
	Interest rate swaps	2	6/28/30		(4,878	)		3,087			17,043
				$	(12,272	)	$	5,273		$	36,875
	December 31, 2012
	Interest rate swaps	6	6/30/33	$	(952	)	$	(1,962	)	$	(2,914	)
	Interest rate swaps	7	3/15/20		(5,558	)		(16,568	)		(1,835	)
	Interest rate swaps	2	6/28/30		(4,972	)		(13,865	)		(6,421	)
				$	(11,482	)	$	(32,395	)	$	(11,170	)
	December 31, 2011
	Interest rate swaps	7	3/15/20	$	(4,929	)	$	(15,362	)	$	(11,251	)
	Interest rate swaps	2	6/28/30		—			(12,416	)		(12,416	)
				$	(4,929	)	$	(27,778	)	$	(23,667	)
	Gulf Wind
	In 2010, Gulf Wind entered into interest rate swaps with each of its lenders to manage exposure to interest rate risk on its long-term debt. The interest rate swaps exchange variable interest rate payments for fixed interest rate payments that were approximately 6.6% for the years ended December 31, 2013, 2012 and 2011. The fixed interest rate is set at 6.6% for years two through eight and 7.1% and 7.6% for the last two years of the loan term, respectively. The interest rate swaps qualify for hedge accounting and were designated as cash flow hedges. No ineffectiveness was recorded for the years ended December 31, 2013, 2012 and 2011. The Company expects to reclassify $5.3 million into earnings from accumulated other comprehensive income (loss) during 2014 as quarterly hedge payments occur.
	In 2010, Gulf Wind also entered into an interest rate cap to manage exposure to future interest rates when its long-term debt is expected to be refinanced at the end of the ten-year term. The cap protects the Company if future interest rates exceed approximately 6.0%. The cap has an effective date of March 31, 2020, terminates on December 31, 2024, and has a notional amount of $42.1 million which reduced quarterly during its term. The cap is a derivative but does not qualify for hedge accounting and has not been designated. The Company recognized unrealized gains (losses) of $0.2 million, zero and ($0.3) million for the years ended December 31, 2013, 2012 and 2011, respectively, in unrealized gain (loss) on derivatives in the consolidated statements of operations. The derivative instrument’s asset value as of December 31, 2013, 2012 and 2011, was approximately $0.7 million, $0.4 million and $0.5 million, respectively.
	In 2010, Gulf Wind acquired an energy derivative instrument to manage its exposure to variable electricity prices. The energy price swap fixes the price of approximately 58% of its electricity generation through April 2019. The energy derivative instrument is a derivative but did not meet the criteria required to adopt hedge accounting. The energy derivative instrument’s fair value as of December 31, 2013, 2012 and 2011 was $68.4 million, $79.6 million and $86.6 million, respectively. Gulf Wind recognized unrealized (losses) gain of ($11.3) million, ($7.0) million, and $17.6 million for the years ended December 31, 2013, 2012 and 2011, respectively, in unrealized (loss) gain on energy derivative in the consolidated statements of operations.
	Spring Valley
	In 2011, Spring Valley entered into interest rate swaps with its lenders to manage exposure to interest rate risk on its long-term debt. The interest rate swaps exchange variable interest rate payments for fixed interest rate payments of approximately 5.5% for the first four years of its term debt and increases by 0.25% every four years, thereafter. The interest rate swaps qualify for hedge accounting and were designated as cash flow hedges. No ineffectiveness was recorded for the years ended December 31, 2013, 2012 and 2011. The Company expects to reclassify $4.9 million into earnings from accumulated other comprehensive income (loss) during 2014 as quarterly swap settlement payments occur.
	Ocotillo
	In October 2012, Ocotillo entered into interest rate swaps with its lenders to manage exposure to interest rate risk on its long-term debt. The interest rate swaps exchange variable interest rate payments for fixed interest rate payments of approximately 2.5% and 2.2% for the development bank term loans and the commercial bank term loans, respectively. The interest rate swaps for the development bank loans qualify for hedge accounting and were designated as cash flow hedges. No ineffectiveness was recorded for the years ended December 31, 2013, 2012 and 2011. The Company expects to reclassify $2.1 million into earnings from accumulated other comprehensive income (loss) during 2014 as quarterly hedge payments occur. The interest rate swaps for the commercial bank loans are undesignated derivatives that are used to mitigate exposure to variable interest rate debt.

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	11	Accumulated Other Comprehensive Income (Loss)
	The following table summarizes changes in the accumulated other comprehensive income (loss) balance by component:
		Foreign			Effective Portion of			Proportionate			Total
		Currency			Change in Fair Value			Share of Equity
					of Derivatives			Investee’s OCI
	Balances at January 1, 2011	$	(497	)	$	(9,040	)	$	—		$	(9,537	)
	Current period other comprehensive loss		(2,406	)		(23,667	)		—			(26,073	)
	Income tax benefit (expense)		—			—			—			—
	Balances at December 31, 2011		(2,903	)		(32,707	)		—			(35,610	)
	Current period other comprehensive income (loss)		2,749			(11,170	)		(1,475	)		(9,896	)
	Income tax benefit (expense)		—			—			—			—
	Balances at December 31, 2012		(154	)		(43,877	)		(1,475	)		(45,506	)
	Current period other comprehensive income (loss)		(8,309	)		36,875			2,621			31,187
	Income tax expense		—			—			(148	)		(148	)
	Grand acquisition		—			—			(4,217	)		(4,217	)
	Income tax benefit—Grand acquisition		—			—			1,307			1,307
	Balances at December 31, 2013	$	(8,463	)	$	(7,002	)	$	(1,912	)	$	(17,377	)

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	12	Fair Value Measurements
	The Company’s fair value measurements incorporate various factors, including the credit standing and performance risk of the counterparties, the applicable exit market, and specific risks inherent in the instrument. Nonperformance and credit risk adjustments on risk management instruments are based on current market inputs when available, such as credit default hedge spreads. When such information is not available, internal models may be used.
	Assets and liabilities recorded at fair value in the consolidated financial statements are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels directly related to the amount of subjectivity associated with the inputs to valuation of these assets or liabilities are as follows:
	Level 1—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.
	Level 2—Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.
	Level 3—Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities and which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuations technique and the risk inherent in the inputs to the model.
	Short-term financial instruments consist principally of cash, cash equivalents, accounts receivable, notes receivable, accounts payable and other accrued liabilities. Based on the nature and short maturity of these instruments their fair value is approximated using carrying cost and they are presented in the Company’s financial statements at carrying cost. The fair values of cash, cash equivalents and restricted cash are a Level 1 hierarchy. The fair values of accounts receivable, notes receivable, accounts payable and other accrued liabilities are Level 2 hierarchy.
	Long term debt is presented on the consolidated balance sheet at amortized cost. The fair value of variable interest rate long-term debt is approximated by its carrying cost. The fair value of fixed interest rate long-term debt is estimated based on observable market prices or parameters or derived from such prices or parameters (Level 2). Where observable prices or inputs are not available, valuation models are applied, using the net present value of cash flow streams over the term using estimated market rates for similar instruments and remaining terms (Level 3).
	Derivatives and contingent liabilities subject to re-measurement are presented in the financial statements at fair value. The interest rate swaps and interest rate cap were valued by discounting the net cash flows using the forward LIBOR curve with the valuations adjusted by the counterparties’ credit default hedge rate (Level 2). The fair value of contingent liabilities is based upon the time of realization and the probability of the contingent event (Level 3). The energy derivative instrument was valued by discounting the projected net cash flows over the remaining life of the derivative using forward energy curves adjusted by a nonperformance risk factor (Level 3).
	The following tables present the fair values according to each defined level (in thousands):
	Financial assets and (liabilities) measured on a recurring basis:
		Fair Value Measurements Using
		Level 1			Level 2			Level 3
	December 31, 2013
	Interest rate swaps	$	—		$	3,460		$	—
	Interest rate cap		—			681			—
	Energy derivative		—			—			68,353
		$	—		$	4,141		$	68,353
	December 31, 2012
	Interest rate swaps	$	—		$	(48,788	)	$	—
	Interest rate cap		—			447			—
	Energy derivative		—			—			79,625
	Contingent liabilities		—			—			(8,001	)
		$	—		$	(48,341	)	$	71,624
	Reconciliation of energy derivative and contingent liabilities measured at fair value using unobservable inputs (Level 3):
		Contingent			Energy			Total
		Liabilities			Derivative
	Balances at January 1, 2012	$	(5,986	)	$	86,577		$	80,591
	Settlements		—			(19,644	)		(19,644	)
	Change in fair value, net of settlements		(2,015	)		12,692			10,677
	Balances at December 31, 2012		(8,001	)		79,625			71,624
	Settlements		8,001			(16,798	)		(8,797	)
	Change in fair value, net of settlements		—			5,526			5,526
	Balances at December 31, 2013	$	—		$	68,353		$	68,353
	The change in fair value for the years ended December 31, 2013, 2012 and 2011 related to assets and liabilities still held at the end of the respective period, except for contingent liabilities which were settled during the year ended December 31, 2013.
	The following table presents the carrying amounts and fair values of the Company’s long term debt (in thousands):
		December 31, 2013						December 31, 2012
		Carrying			Fair Value			Carrying			Fair Value
		Amount						Amount
	Total long term debt	$	1,249,218		$	1,165,119		$	1,290,570		$	1,247,449

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	13	Income Taxes
	The following table presents significant components of the provision for income taxes (in thousands):
		Year ended December 31,
		2013			2012			2011
	Current
	U.S. federal	$	—		$	—		$	—
	State		—			—			—
	Foreign		—			—			—
			—			—			—
	Deferred
	U.S. federal		2,961			—			—
	State		—			—			—
	Foreign		1,585			(3,604	)		689
			4,546			(3,604	)		689
	Total income tax (benefit) provision	$	4,546		$	(3,604	)	$	689
	The following table presents the domestic and foreign components of net income (loss) before income tax (benefit) expense (in thousands):
		Year ended December 31,
		2013			2012			2011
	U.S.	$	4,022		$	(17,810	)	$	25,957
	Foreign		10,596			830			638
	Total	$	14,618		$	(16,980	)	$	26,595
	The following table presents a reconciliation of the statutory U.S federal income tax rate to the Company’s effective tax rate, as a percentage of income before taxes for the years ended December 31, 2013, 2012 and 2011:
		Year ended December 31,
		2013			2012			2011
	Statutory U.S. federal tax rate		35	%		35	%		35	%
	Book/tax basis difference		—			27.2	%		—
	Partnership income not subject to taxes		—			(40.9	)%		(32.4	)%
	Adjustment for income in non-taxable entities allocable to noncontrolling interest		16.5	%		—			—
	Foreign rate difference
	Tax rate differential on pre-tax book income, other		2.1	%		—			—
	Local tax on branch profits/(losses)—Puerto Rico		13.1	%		—			—
	Permanent book/tax differences (domestic only)		(2.2	)%		—			—
	Valuation allowance		187.2	%		—			—
	Other		3.1	%		—			—
	ARRA Section 1603 grant-basis reduction deferred tax assets		(223.7	)%		—			—
	Effective income tax rate		31.1	%		21.3	%		2.6	%
	The following table presents significant components of the Company’s deferred tax assets and deferred tax liabilities as of December 31, 2013 and 2012 (in thousands):
		December 31,
		2013			2012
	Deferred tax assets/liabilities—current
	Other current deferred tax assets and liabilities	$	2,399		$	—
	Basis difference in derivatives		2,835			—
	Total gross deferred tax assets/(liabilities)		5,234			—
	Less: valuation allowance		(4,661	)		—
	Total net deferred tax assets/(liabilities)—current		573			—
	Deferred tax assets/(liabilities)—non-current:
	Property, plant and equipment		(36,548	)		(47,894	)
	Basis difference in foreign subsidiaries		40,097			—
	Partnership interest		(4,917	)		—
	Lease Hatchet Ridge		29,314			—
	Asset retirement obligation		4,649			—
	Equity method		3,794			—
	Unrealized loss on derivatives		(5,830	)		—
	Net operating loss carryforwards		61,441			45,302
	Other non current deferred tax assets and liabilities		(4,595	)		(690	)
	Change in tax status		—			4,599
	Accruals not currently deductible		—			443
	Total gross deferred tax assets/(liabilities)—non-current		87,405			1,760
	Less: valuation allowance		(95,318	)		(482	)
	Total net deferred tax assets/(liabilities)—non-current		(7,913	)		1,278
	Total net deferred tax assets/(liabilities)	$	(7,340	)	$	1,278
	The deferred tax assets and deferred tax liabilities resulted primarily from temporary differences between book and tax basis of assets and liabilities. The Company regularly assesses the likelihood that future taxable income levels will be sufficient to ultimately realize the tax benefits of the deferred tax assets. Should the Company determine that future realization of the tax benefits is not more likely than not, additional valuation allowance would be established which would increase the Company’s tax provision in the period of such determination. The net deferred tax assets and net deferred tax liabilities as of December 31, 2013 and 2012 are attributed primarily to the Company’s Canadian and Puerto Rico entities. The net change in valuation allowance increased by $99.5 million during year ended December 31, 2013. The net increase is attributable to the contribution transactions of $79.3 million and the three month activity ended December 31, 2013 in the U.S. consolidated filing group of $20.2 million.
	As of December 31, 2013, the Company had U.S federal and state net operating loss carryforwards of approximately $77.6 million and $77.8 million, respectively. These net operating loss carryforwards are available to reduce future taxable income and will begin to expire commencing in 2033 for federal and state purposes.
Internal Revenue Code Section 382 places a limitation ( the “Section 382 Limitation”) on the amount of taxable income that can be offset by net operating loss (“NOL”) carryforwards after a change in control (generally greater than 50% change in ownership) of a loss corporation. California has similar rules. The Company did not have any historic US net operating losses prior to October 2, 2013 except for net operating losses from its Puerto Rico entity which may be subject to Section 382 limitation.
The Company is required to recognize in the financial statements the impact of a tax position, if that position is more likely than not of being sustained on audit, based on the technical merits of the position. As of December 31, 2013, the Company does not have any unrecognized tax benefits and does not have any tax positions for which it is reasonably possible that the amount of gross unrecognized tax benefits will increase or decrease within 12 months after the year ended December 31, 2013.
The Company files income tax returns in the U.S federal jurisdiction, various state jurisdictions and foreign jurisdictions for its Canadian and Chilean operations. The Company’s U.S and foreign income tax returns for 2009 and forward are subject to examination.
The Company has a policy to classify accrued interest and penalties associated with uncertain tax positions together with the related liability, and the expenses incurred related to such accruals are included in the provision for income taxes. The Company did not incur any interest expense or penalties associated with unrecognized tax benefits for the years ended December 31, 2013, 2012 and 2011.
The Company operates under a tax holiday in Puerto Rico which enacted a special tax rate of 4% for business dedicated to the production of energy for consumption through the use of renewal sources. Pursuant to Act 83 as of July 19, 2010, the Green Energy Incentives Act (“GEIA”), promotes the development of green energy projects through economic incentives so as to reduce the island’s dependency on oil. The GEIA provides for a 4% flat income tax rate on green energy income (“GEI”) in lieu of any income tax imposed by the Puerto Rico Code for a 25 year period and is scheduled to terminate on December 31, 2036. The impact of the tax holiday decreased foreign deferred tax benefit by $0.2 million for 2013. The impact of the tax holiday on net income per diluted share was $0.006.

Stockholders_Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Stockholders' Equity	'
	14	Stockholders’ Equity
	Common Stock
	A summary of the rights and preferences of the Company’s Class A and Class B common stock as of December 31, 2013 is as follows:
	Voting Rights
	The rights of the holders of the Company’s Class A and Class B shares are identical other than in respect of dividends and the conversion rights of the Class B shares. While each Class A and Class B share have one vote on all matters submitted to a vote of the Company’s stockholders, Class B shares have no rights to dividends or distributions (other than upon liquidation). In the case of a proposed amendment to the Company’s amended and restated certificate of incorporation affecting its Class A shares and/or its Class B shares, holders of Class A shares and holders of Class B shares will each be entitled to vote separately as a class to approve such amendment. Upon the later of December 31, 2014 and the date on which its South Kent project has achieved commercial operations (“Conversion Event”), all of the outstanding Class B shares will automatically convert, on a one-for-one basis, into Class A shares. Other than upon occurrence of the Conversion Event, there are no conversion rights attaching to the Class B shares. Other than in certain circumstances involving a take-over bid, tender offer or merger or similar business combination in respect of the Company, in which circumstance a transfer of Class B shares to the acquirer, and subsequently among the acquirer and its officers, employees and affiliates, would be permitted, the Company’s Class B shares will not be transferrable except to and among Pattern Development, the Company and its respective officers, employees and affiliates. No subdivision or consolidation of Class B shares can be made unless the same subdivision or consolidation of the Class A shares is made concurrently.
	Dividend Rights
	Holders of Class A stock are eligible to receive dividends on common stock held when funds are available and as approved by the Board of Directors. Holders of Class B common stock are not entitled to dividends. In November 2013, the Company’s Board of Directors declared a quarterly cash dividend of $0.3125 per Class A share for the fourth quarter, which represents $1.25 on an annualized basis. The dividend was paid on January 30, 2014 to stockholders of record as of December 31, 2013.
	Liquidation Rights
	In the event of any liquidation, dissolution or winding-up of the Company, holders of Class A shares will be entitled to share ratably, together with holders of Class B shares, in the Company’s assets that remain after payment or provision for payment of all of its debts and obligations and after liquidation payments to holders of outstanding shares of preferred stock, if any.
	Preferred Stock
	The Company has 100,000,000 shares of authorized preferred stock issuable in one or more series. The Company’s Board of Directors is authorized to determine the designation, powers, preferences and relative, participating, optional or other special rights of any such series. As of December 31, 2013 and 2012, there was no preferred stock issued and outstanding.

Equity_Incentive_Award_Plan

Equity Incentive Award Plan	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Equity Incentive Award Plan	'
	15	Equity Incentive Award Plan
	In September 2013, the Company adopted the 2013 Equity Incentive Award Plan (“2013 Plan”) , which permits the Company to issue 3,000,000 aggregate number of Class A common shares for equity awards including incentive and nonqualified stock options, restricted stock awards (“RSAs”) and restricted stock units to employees, directors and consultants. RSAs provide the holder with immediate voting rights, but are restricted in all other respects until released. Upon cessation of services to the Company, any unreleased RSAs will be cancelled. All unreleased RSAs accrue dividends and distributions, and are paid in cash upon release. In 2013, the Company made an initial grant of 444,823 stock options and 83,183 RSAs to certain employees in connection with the IPO and additional grants of 3,437 RSAs to certain directors. As of December 31, 2013, 2,468,557 aggregate number of Class A shares were available for issuance under the 2013 Plan.
	Restricted Stock Awards
	The following table summarizes restricted stock awards activity under the 2013 Plan for the year ended December 31, 2013:
		Number of RSAs			Weighted Average		Aggregate
		Outstanding			Grant Date		Intrinsic
					Fair Value		Value
	Balance at October 2, 2013		—		$	—
	Granted		86,620			22.71
	Released		(9,424	)		24.15
	Repurchased for employee tax withholding		(934	)		22.53
	Balance at December 31, 2013		76,262		$	22.53	$	2,311,501
	For the year ended December 31, 2013, the total fair value of restricted stock awards released was $0.2 million, based on the weighted average grant date fair value.
	Stock Options
	The following table summarizes stock option activity under the 2013 Plan for the year ended December 31, 2013:
		Number of			Weighted Average		Weighted Average		Aggregate
		Options			Exercise Price		Remaining		Instrinsic Value
		Outstanding					Contractual Life
							(in years)
	Balance at October 2, 2013		—		$	—
	Granted		444,823			22.00
	Vested		(37,069	)		22
	Exercised		—			—
	Expired		—			—
	Forfeited		—			—
	Balance at December 31, 2013		407,754		$	22		9.8	$	3,388,436
	Exercisable at December 31, 2013		37,069		$	22		9.8	$	308,043
	Aggregate intrinsic value represents the value of the Company’s closing stock price of $30.31 on the last trading day of the period in excess of the weighted-average exercise price multiplied by the number of options outstanding or exercisable.
	Stock-Based Compensation
	The Company accounts for stock-based compensation related to stock options granted to employees by estimating the fair value of the stock-based awards using the Black-Scholes option-pricing model. The fair value of the stock options granted are amortized over the applicable vesting period. The Black-Scholes option pricing model includes assumptions regarding dividend yields, expected volatility, expected option term, expected forfeiture rate and risk-free interest rates. The Company estimates expected volatility based on the historical volatility of comparable publicly traded companies for a period that is equal to the expected term of the options. The risk-free interest rate is based on the U.S. treasury yield curve in effect at the time of grant for a period commensurate with the estimated expected life. The expected term of options granted is derived using the “simplified” method as allowed under the provisions of the ASC 718, Compensation—Stock Compensation, due to insufficient historical exercise history data to provide a reasonable basis upon which to estimate expected term due to the limited period of time its equity shares have been publicly traded. As such, expected term of options represents the period of time that options granted are expected to be outstanding.
	As of December 31, 2013, the fair value of employee stock options was estimated using the Black-Scholes option pricing model. The following weighted average assumptions were used:
		Year ended
		December 31, 2013
	Stock options:
	Risk-free interest rate		1.68	%
	Expected life (in years)		5.8
	Expected volatility		36	%
	Expected dividend yield		5.7
	The Company measures the fair value of RSAs at the grant date and accounts for stock-based compensation by amortizing the fair value on a straight line basis over the related vesting period.
	The stock-based compensation expense related to stock options and RSAs is recorded as a component of general and administrative expenses in the Company’s consolidated statements of operations and totaled $0.5 million for the year ended December 31, 2013.
	As of December 31, 2013, the total unrecorded stock-based compensation expense for unvested restricted stock awards was $1.7 million, which is expected to be amortized over a weighted-average period of 2.8 years. As of December 31, 2013 the total unrecorded stock-based compensation expense for unvested stock options shares was $1.7 million, which is expected to be amortized over a weighted-average period of 2.8 years.

Earnings_Per_Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	16	Earnings Per Share
	The Company computes earnings per share (EPS) for Class A and Class B common stock using the two-class method for participating securities. The rights, including voting and liquidation rights, of the holders of the Class A and Class B common stock are identical, except with respect to dividends, as the Class B common stock is not entitled to dividends.
	Basic EPS is computed by dividing the net income attributable to common stockholders by the weighted-average number of common shares outstanding, for each respective class of stock. Net income attributable to common stockholders is allocated to each class of common stock considering dividends declared or accumulated during the current period that must be paid for the current period and the allocation of undistributed earnings to the extent that each class of stock may share in earnings as if all of the earnings for the period had been distributed. Because our Class B shares are not entitled to dividends, undistributed earnings, if any, would be allocated entirely to the Class A shares.
	Diluted EPS is computed by dividing net income attributable to common stockholders by the weighted-average number of common shares and potentially dilutive common shares outstanding, for each respective class of stock. Potentially dilutive common stock includes the dilutive effect of the common stock underlying in-the-money stock options and is calculated based on the average share price for each period using the treasury stock method. Potentially dilutive common stock also reflects the dilutive effect of unvested restricted stock awards.
	Class B common stock is a contingently convertible security which is convertible to Class A common stock on a one-to-one basis on the later of December 31, 2014 or commencement of commercial operations of the South Kent wind project. The computation of diluted EPS of Class A common stock would include the impact of the conversion of the Class B common stock, if dilutive for Class A, using the if-converted method once the contingency surrounding the conversion has been met.
	In periods of net loss, the loss is allocated by first considering any dividends declared or accumulated to Class A common stock. While Class B is not entitled to dividends, because it has the same voting, liquidation and residual rights as Class A, the remaining undistributed loss is allocated equally per share to weighted average Class A and Class B common stock outstanding during the year. For the period from October 2, 2013 to December 31, 2013, potentially dilutive securities were excluded from the diluted EPS calculation as their effect is anti-dilutive.
	The following table provides a disaggregated presentation of the Company’s consolidated statements of operations before and after its IPO on October 2, 2103:
	Pattern Energy Group Inc.
	Consolidated Statements of Operations
	(In thousands of U.S. dollars, except share data)
		From October 2, 2013			From January 1, 2013			For Year Ended
		to December 31, 2013			to October 1, 2013			December 31, 2013
	Revenue:
	Electricity sales	$	41,836		$	131,434		$	173,270
	Energy derivative settlements		4,035			12,763			16,798
	Unrealized loss on energy derivative		(4,916	)		(6,356	)		(11,272	)
	Related party revenue		446			465			911
	Other revenue		701			21,165			21,866
	Total revenue		42,102			159,471			201,573
	Cost of revenue:
	Project expense		15,455			42,222			57,677
	Depreciation and accretion		21,193			61,987			83,180
	Total cost of revenue		36,648			104,209			140,857
	Gross profit		5,454			55,262			60,716
	Total operating expenses		3,456			9,532			12,988
	Operating income		1,998			45,730			47,728
	Other expense		(10,217	)		(22,893	)		(33,110	)
	Net (loss) income before income tax		(8,219	)		22,837			14,618
	Tax provision (benefit)		11,314			(6,768	)		4,546
	Net (loss) income		(19,533	)		29,605			10,072
	Net loss attributable to noncontrolling interest		(6,197	)		(690	)		(6,887	)
	Net (loss) income attributable to controlling interest	$	(13,336	)	$	30,295		$	16,959
	Earnings per share information:
	Less: Net income attributable to controlling interest prior to the IPO on October 2, 2013								(30,295	)
	Net loss attributable to controlling interest subsequent to the IPO							$	(13,336	)
	Numerator for basic and diluted earnings (loss) per share:
	Net earnings (loss)							$	(13,336	)
	Less: dividends declared
	Class A common stock								(11,103	)
	Class B common stock								—
								$	(24,439	)
	Undistributed earnings (loss)
	Denominator for basic and diluted earnings (loss) per share:
	Weighted average number of shares:
	Class A common stock								35,448,056
	Class B common stock								15,555,000
	Total								51,003,056
	Calculation of basic and diluted earnings (loss) per share:
	Class A common stock:
	Dividends							$	0.31
	Undistributed loss								(0.48	)
	Basic and diluted loss per share							$	(0.17	)
	Class B common stock:
	Dividends							$	—
	Undistributed loss								(0.48	)
	Basic and diluted loss per share							$	(0.48	)

Geographic_Information

Geographic Information	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Geographic Information	'
	17	Geographic Information
	The table below provides information, by country, about the Company’s consolidated operations. Revenue is recorded in the country in which it is earned and assets are recorded in the country in which they are located (in thousands):
		Revenue						Property, Plant and Equipment, net
		Year ended December 31,						December 31,
		2013		2012		2011		2013		2012
	United States	$	161,505	$	73,089	$	103,773	$	1,210,319	$	1,367,149
	Canada		40,068		41,439		32,086		265,823		301,153
	Total	$	201,573	$	114,528	$	135,859	$	1,476,142	$	1,668,302

Commitments_Contingencies_and_

Commitments, Contingencies and Warranties	12 Months Ended
	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitments, Contingencies and Warranties	'
	18	Commitments, Contingencies and Warranties
	From time to time, the Company has become involved in claims and legal matters arising in the ordinary course of business. Management is not currently aware of any matters that will have a material adverse effect on the financial position, results of operations, or cash flows of the Company.
	Power Purchase Agreements
	The Company has various PPAs that terminate from 2025 to 2039. The terms of the PPAs generally provide for the annual delivery of a minimum amount of electricity at fixed prices and in some cases include price escalation over the term of the respective PPAs. As of December 31, 2013, under the terms of the PPAs, the Company issued irrevocable letters of credit totaling $57.2 million to ensure its performance for the duration of the PPAs.
	Project Finance Agreements
	The Company has various project finance agreements which obligate the Company to provide certain reserves to enhance its credit worthiness and facilitate the availability of credit. As of December 31, 2013, the Company issued irrevocable letters of credit totaling $91.8 million, of which $44.8 million was from the Company’s revolving credit facility, to ensure performance under these various project finance agreements.
	Turbine Operations and Maintenance
	The following table presents turbine operations and maintenance commitments over the next five years (in thousands):
	For the year ending December 31,
	2014	$	16,465
	2015		3,845
	2016		2,188
	2017		1,965
	2018		55
	Thereafter		591
	Total	$	25,109
	The Company has six operating projects that have entered into turbine service and maintenance agreements with the turbine supplier or a third party to provide turbine maintenance for terms between two to five years from the in-service date for each of the project’s turbines. Total annualized base fees at December 31, 2013, are approximately $19.4 million, adjusted for inflation.
	Contingent Liabilities
	The Company has recorded contingent purchase price payment obligations related to acquired assets that were recorded at fair value and re-measured at each reporting date. The amount of recorded contingent purchase price obligations was zero and $8.0 million as of December 31, 2013 and 2012, respectively.
	In addition, the Company has unrecorded purchase price payment obligations related to asset acquisitions that are contingent on future events. The amount of unrecorded contingent purchase price obligations was $4.7 million and $2.8 million as of December 31, 2013 and 2012, respectively.
	Land Leases
	The Company has entered into various long-term land leases. Rent expense, included in project expense in the consolidated statements of operations, was $6.1 million, $4.2 million and $4.6 million for the years ended December 31, 2013, 2012 and 2011, respectively.
	The future minimum payments related to these leases as of December 31, 2013, are as follows (in thousands):
	For the year ending December 31,
	2014	$	3,713
	2015		3,717
	2016		3,725
	2017		3,731
	2018		3,738
	Thereafter		91,876
	Total	$	110,500
	Purchase Commitments
	The Company has entered into various commitments with service providers related to the Company’s projects and operations of its business. Outstanding commitments with these vendors, excluding turbine operations and maintenance commitments were $4.1 million and $5.1 million as of December 31, 2013 and 2012, respectively. The Company has open commitments for the purchase of new wind turbines of zero and $1.7 million, as of December 31, 2013 and 2012, respectively, and for construction of zero and $22.3 million as of December 31, 2013 and 2012, respectively.
	Purchase and Sales Agreement
	On December 20, 2013, the Company entered into an agreement with Pattern Development to acquire approximately 80% of the ownership interest in Panhandle 2, a 182 MW wind project being built in Carson County, Texas, for approximately $122.9 million in cash. The acquisition, which includes assumption by the Company of certain tax indemnities, is expected to close in fourth quarter of 2014 upon completion of construction, and the Company expects to fund the purchase with available cash and credit facilities.
	Indemnity
	The Company provides a variety of indemnities in the ordinary course of business to contractual counterparties and to our lenders and other financial partners. Hatchet Ridge agreed to indemnify the lender that provided financing for Hatchet Ridge against certain tax losses in connection with its sale-leaseback financing transaction in December 2010. The indemnity agreement is effective for the duration of the sale-leaseback financing.
	The Company is party to certain indemnities for the benefit of the Spring Valley, Santa Isabel and Ocotillo project finance lenders. These indemnity obligations consist principally of indemnities that protect the project finance lenders from the potential effect of any recapture by the U.S. Department of the Treasury, or “U.S. Treasury,” of any amount of the ITC cash grants previously received by the projects. The ITC cash grant indemnity obligations guarantee amounts of any cash grant made to each of the respective projects that may subsequently be recaptured. In addition, the Company is also party to an indemnity of our Ocotillo project finance lenders in connection with certain legal matters, which is limited to the amount of certain related costs and expenses.
	Santa Isabel agreed to indemnify unrelated third parties against certain tax losses in connection with monetization of tax credits under the Economic Incentives for the Development of Puerto Rico Act of May 28, 2008 for $7.2 million.
	Turbine Availability Warranties
	The Company has various turbine availability warranties from its turbine manufacturers. Pursuant to these warranties, if a turbine operates at less than minimum availability during the warranty period, the turbine manufacturer is obligated to pay as liquidated damages a fee for each percent that the turbine operates below the minimum availability threshold. In addition, also pursuant to certain of these warranties, if a turbine operates at more than a specified availability during the warranty period, the Company has an obligation to pay a bonus to the turbine manufacturer. During 2012 and 2011, no liquidating damages or bonus were recorded by the Company.
	In 2013, the Company entered into warranty settlements with a turbine manufacturer for blade related wind turbine outages. The warranty settlements provide for total liquidated damage payments of approximately $21.9 million for the year ended December 31, 2013. During the year ended December 31, 2013, the Company received payments of $24.1 million in connection with these warranty settlements. The Company estimates the maximum future refund of liquidated damage payments to the turbine manufacturer to be $2.2 million and has recorded an accrued liability for this amount as of December 31, 2013. The warranty settlements received, net of the maximum potential future refund to the wind turbine manufacturer, have been recorded as other revenue in the consolidated statements of operations.

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Related Party Transactions	'
	19	Related Party Transactions
	From inception to October 1, 2013, the Company’s project management and administrative activities were provided by Pattern Development. Costs associated with these activities were allocated to the Company and recorded in its consolidated statements of operations. Allocated costs include cash and non-cash compensation, other direct, general and administrative costs, and non-operating costs deemed allocable to the Company. Measurement of allocated costs is based principally on time devoted to the Company by officers and employees of Pattern Development. The Company believes the allocated costs presented in its consolidated statements of operations are a reasonable estimate of actual costs incurred to operate the business. The allocated costs are not the result of arms-length, free-market dealings.
	Management Services Agreement and Shared Management
	Effective October 2, 2013, the Company entered into a bilateral Management Services Agreement with Pattern Development which provides for the Company and Pattern Development to benefit, primarily on a cost-reimbursement basis, plus a 5% fee on certain direct costs, from the parties’ respective management and other professional, technical and administrative personnel, all of whom will report to and be managed by the Company’s executive officers. Pursuant to the Management Services Agreement, certain of the Company’s executive officers, including its Chief Executive Officer, will also serve as executive officers of Pattern Development and devote their time to both the Company and Pattern Development as is prudent in carrying out their executive responsibilities and fiduciary duties. The Company refers to the employees who will serve as executive officers of both the Company and Pattern Development as the “shared PEG executives.” The shared PEG executives will have responsibilities for both the Company and Pattern Development and, as a result, these individuals will not devote all of their time to the Company’s business. Under the terms of the Management Services Agreement, Pattern Development is required to reimburse the Company for an allocation of the compensation paid to such shared PEG executives reflecting the percentage of time spent providing services to Pattern Development.
	The table below presents allocated costs prior to October 2, 2013 and net bilateral management service cost reimbursements on and after October 2, 2013 included in the consolidated statements of operations (in thousands):
		December 31,
		2013			2012			2011
	Project expense	$	1,995		$	1,998		$	1,139
	General and administrative		7,318			10,604			8,098
	Management Services Agreement expense		851			—			—
	Management Services Agreement income		(665	)		—			—
	Other income		(551	)		(210	)		(199	)
	Total	$	8,948		$	12,392		$	9,038
	Prior to the Contribution Transactions, the Company had purchase arrangements with Pattern Development under which the latter purchased various services and supplies on behalf of the Company and received reimbursement for these purchases. As of December 31, 2013 and 2012, the amounts payable to Pattern Development for these purchases were $1.2 million and $0.2 million, respectively.
	Letters of credit, indemnities and guarantees
	Pattern Development provided letters of credit that secure the Company’s obligations under PPAs and interconnection agreements. There were no letters of credit outstanding as of December 31, 2013 and 2012, respectively.
	Pattern Development agreed to guarantee $14.0 million of El Arrayán’s payment obligations to a lender that has provided a $20 million credit facility for financing of El Arrayán’s recoverable, construction-period value added tax payments. The remaining $6.0 million of the credit facility has been guaranteed by another investor in El Arrayán.
	Purchase and Sales Agreements
	On December 20, 2013, the Company entered into an agreement with Pattern Development to acquire approximately 80% of the ownership interest in Panhandle 2, a 182 MW wind project being built in Carson County, Texas, for approximately $122.9 million in cash. The acquisition is expected to close in fourth quarter of 2014 upon completion of construction, and the Company expects to fund the purchase with available cash and credit facilities.
	On December 20, 2013, the Company acquired a 45.0% equity interest in Grand from Pattern Development. Subject to the terms of this agreement, the Company may make an additional contingent payment of up to $4.7 million to Pattern Development in 2014.
	Puerto Rico Electric Power Authority (PREPA)
	The Company’s Santa Isabel project was in a dispute with PREPA over the appropriate rate being charged to the project for the electric services it uses. During the year ended December 31, 2013, the difference between what the Company believes is the appropriate monthly charge and PREPA’s bill was resolved in principle, and billing is now per the understanding between the parties. Pattern Development provided the Company with an indemnity to mitigate the economic impact on the Company of this dispute.
	Management fees
	The Company provides operations and management services and receives a fee for such services under agreements with South Kent, Grand and El Arrayán, its joint venture investees. Management fees of $0.9 million were recorded as related party revenue in the consolidated statements of operations for the year ended December 31, 2013 and a related party receivable of $0.2 million was recorded in the consolidated balance sheet as of December 31, 2013. The Company eliminates the intercompany profit from management fees related to its ownership interest in South Kent.
	Employee Savings Plan
	The Company participates in a 401(k) plan sponsored and maintained by Pattern Development, established on August 3, 2009 and restated on October 3, 2013. The Company also sponsors a Canadian Registered Retirement Savings Plan (“RRSP”), established on October 2, 2013. Participants in the plans are allowed to defer a portion of their compensation, not to exceed the respective Internal Revenue Service (IRS) or Canada Revenue Agency (CRA) annual allowance contribution guidelines, and are 100% vested in their respective deferrals and earnings. Participants may choose from a variety of investment options. The Company contributes 5% of base compensation to each employee’s 401(k) or RRSP account, up to the annual compensation limit. For the year ended December 31, 2013, the Company contributed $0.1 million which was recorded in the consolidated statements of operations as either general and administrative expense or cost of revenue. No such contributions were made during the years ended December 31, 2012 and 2011.

Selected_Quarterly_Financial_D

Selected Quarterly Financial Data	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Selected Quarterly Financial Data	'
	20	Selected Quarterly Financial Data (Unaudited)
	The following tables summarize the Company’s unaudited quarterly consolidated statements of operations for each of the eight quarters in the period ended December 31, 2013. The quarterly consolidated statements of operations data were prepared on a basis consistent with the audited consolidated financial statements included in Part III, Item 14, “Financial Statements and Supplementary Data” in this Annual Report on Form 10-K.
	Quarterly financial data in thousands, except for share data:
		Three months ended
		December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013
	Revenue	$	41,767		$	57,257		$	58,712		$	43,837
	Gross profit		4,729			21,471			26,222			8,294
	Net (loss) income		(19,376	)		4,244			43,988			(18,784	)
	Net (loss) income attributable to noncontrolling interest		(6,197	)		3,248			(359	)		(3,579	)
	Net (loss) income attributable to controlling interest		(13,179	)		996			44,347			(15,205	)
	Basic and diluted loss per share—Class A	$	(0.17	)		N/A			N/A			N/A
	Basic and diluted loss per share—Class B	$	(0.48	)		N/A			N/A			N/A
		Three months ended
		December 31,			September 30,			June 30,			March 31,
		2012			2012			2012			2012
	Revenue	$	34,345		$	16,903		$	24,939		$	38,341
	Gross profit (loss)		10,086			(5,213	)		6,175			19,610
	Net (loss) income		(4,455	)		(16,913	)		(575	)		8,567
	Net (loss) income attributable to noncontrolling interest		(1,147	)		(7,494	)		(2,928	)		4,480
	Net (loss) income attributable to controlling interest		(3,308	)		(9,419	)		2,353			4,087
	Basic and diluted loss per share—Class A		N/A			N/A			N/A			N/A
	Basic and diluted loss per share—Class B		N/A			N/A			N/A			N/A

Subsequent_Events

Subsequent Events	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	21	Subsequent Events
	None.

Schedule_ICondensed_ParentComp

Schedule I-Condensed Parent-Company Financial Statements	12 Months Ended
	Dec. 31, 2013
Condensed Financial Information Of Parent Company Only Disclosure [Abstract]	'
Schedule I-Condensed Parent-Company Financial Statements	'
	Schedule I—Condensed Parent-Company Financial Statements
	Pattern Energy Group Inc.
	Condensed Financial Information of Parent
	Balance Sheets
	(In thousands of U.S. dollars, except share data)
		December 31,			December 31,
		2013			2012
	Assets
	Current assets:
	Cash and cash equivalents	$	75,776		$	1
	Related party receivable		1,000			—
	Prepaid expenses and other current assets		446			—
	Total current assets		77,222			1
	Investments in subsidiaries		407,271			514,117
	Net deferred tax assets		573			—
	Total assets	$	485,066		$	514,118
	Liabilities and equity
	Current liabilities:
	Accounts payable and other accrued liabilities	$	4,513		$	7
	Related party payable		667			—
	Dividend payable		11,103			—
	Total current liabilities		16,283			7
	Net deferred tax liabilities		573			—
	Total liabilities		16,856			7
	Equity:
	Class A common stock, $0.01 par value per share:
	500,000,000 shares authorized; 35,530,786 and 100 shares issued and outstanding as of December 31, 2013 and 2012, respectively		355			—
	Class B common stock, $0.01 par value per share:
	20,000,000 shares authorized; 15,555,000 shares issued and outstanding at December 31, 2013		156			—
	Additional paid-in capital		461,828			1
	Capital		—			551,109
	Accumulated income (loss)		14,224			(2,735	)
	Accumulated other comprehensive loss		(8,353	)		(34,264	)
	Total equity		468,210			514,111
	Total liabilities and equity	$	485,066		$	514,118
	Pattern Energy Group Inc.
	Condensed Financial Information of Parent
	Statements of Operations and Comprehensive Income (Loss)
	(In thousands of U.S. dollars)
		Year ended			October 17, 2012
		December 31, 2013			(initial capitalization)
					to December 31, 2012
	Revenue	$	—		$	—
	Expenses		3,630			7
	Operating loss		(3,630	)		(7	)
	Other income (expense):
	Equity in earnings (loss) from subsidiaries		20,487			(2,728	)
	Related party income		665			—
	Other expense, net		(563	)		—
	Other income (expense)		20,589			(2,728	)
	Net income (loss) before income tax		16,959			(2,735	)
	Tax (benefit) provision		—			—
	Net income (loss)		16,959			(2,735	)
	Other comprehensive income (loss), net of tax
	Foreign currency translation, net of tax		(8,309	)		777
	Effective portion of change in fair market value of derivatives, net of tax		31,787			1,099
	Proportionate share of equity investee’s other comprehensive loss, net of tax		2,473			—
	Total other comprehensive income (loss), net of tax		25,951			1,876
	Comprehensive income (loss)	$	42,910		$	(859	)
	Pattern Energy Group Inc.
	Condensed Financial Information of Parent
	Condensed Statements of Cash Flows
	(In thousands of U.S. dollars)
	Year ended			October 17, 2012
	December 31, 2013			(initial capitalization)
				to December 31, 2012
Operating activities
Net income (loss)	$	16,959		$	(2,735	)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation		511			—
Equity in (earnings) loss from subsidiaries		(20,487	)		2,728
Changes in operating assets and liabilities:
Prepaid expenses and other current assets		(446	)		—
Accounts payable and other accrued liabilities		93			7
Related party receivable/payable		(1,007	)		—
Net cash used in operating activities		(4,377	)		—
Investing activities
Distributions from subsidiaries		233,226			—
Contributions to subsidiaries		(172,130	)		—
Net cash provided by investing activities		61,096			—
Financing activities
Repurchase of shares for employee tax withholding		(24	)
Capital contributions		32,678			1
Proceeds from IPO, net of expenses		317,926			—
Capital distributions		(98,884	)		—
Capital distributions—Contribution Transactions		(232,640	)		—
Net cash provided by financing activities		19,056			1
Net change in cash and cash equivalents		75,775			1
Cash and cash equivalents at beginning of period		1			—
Cash and cash equivalents at end of period	$	75,776		$	1
Schedule of non-cash activities
Investments in subsidiaries	$	—		$	514,117

Schedule_II_Supplemental_Finan

Schedule II - Supplemental Financial Statements - South Kent Wind LP	12 Months Ended
	Dec. 31, 2013
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'
Schedule II - Supplemental Financial Statements - South Kent Wind LP	'
	February 21,2014
	Independent Auditor’s Report
	To the Partners of
	South Kent Wind LP
	We have audited the accompanying statement of financial position of South Kent Wind LP as of December 31, 2013 and the related statement of operations and comprehensive income, changes in partners’ capital and cash flows for the year then ended. Management is responsible for these financial statements. Our responsibility is to express an opinion on these financial statements based on our audit.
	We conducted our audit in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. Our audit of the financial statements included examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We were not engaged to perform an audit of the company’s internal control over financial reporting. Our audit included consideration of internal control over financial reporting as a basis for designing audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the company’s internal control over financial reporting. Accordingly, we express no such opinion. Our audit also included performing such other procedures as we considered necessary in the circumstances. We believe that our audit provide a reasonable basis for our opinions.
	In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of South Kent Wind LP as of December 31, 2013 and the results of its operations and their cash flows for the year then ended in conformity with accounting principles generally accepted in the United States of America.
	Chartered Professional Accountants, Licensed Public Accountants
	March 14, 2013
	Independent Auditor’s Report
	To the Partners of
	South Kent Wind LP
	We have audited the accompanying financial statements of South Kent Wind LP, which comprise the balance sheets as at December 31, 2012 and December 31, 2011 and the statements of income, changes in partners’ capital and cash flows for the years then ended, and the related notes, which comprise a summary of significant accounting policies and other explanatory information.
	Management’s responsibility for the financial statements
	Management is responsible for the preparation and fair presentation of the financial statements in accordance with accounting principles generally accepted in the United States of America; this includes the design, implementation, and maintenance of internal control relevant to the preparation and fair presentation of financial statements that are free from material misstatement, whether due to fraud or error.
	Auditor’s responsibility
	Our responsibility is to express an opinion on the financial statements based on our audits. We conducted our audits in accordance with auditing standards generally accepted in the United States of America. Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free from material misstatement.
	An audit involves performing procedures to obtain audit evidence about the amounts and disclosures in the financial statements. The procedures selected depend on our judgment, including the assessment of the risks of material misstatement of the financial statements, whether due to fraud or error. In making those risk assessments, we consider internal control relevant to the entity’s preparation and fair presentation of the financial statements in order to design audit procedures that are appropriate in the circumstances, but not for the purpose of expressing an opinion on the effectiveness of the entity’s internal control. Accordingly, we express no such opinion. An audit also includes evaluating the appropriateness of accounting policies used and the reasonableness of significant accounting estimates made by management, as well as evaluating the overall presentation of the financial statements.
	We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our audit opinion.
	Opinion
	In our opinion, the financial statements referred to above present fairly, in all material respects, the financial position of South Kent Wind LP as at December 31, 2012 and December 31, 2011 and the results of its operations and its cash flows for the years then ended in accordance with accounting principles generally accepted in the United States of America.
	Chartered Professional Accountants, Licensed Public Accountants
	South Kent Wind LP
	Statement of Financial Position
	As at December 31, 2013
	(expressed in Canadian dollars)
			2013			2012
	Assets
	Current assets
	Cash and cash equivalents		$	139,346		$	415,032
	Restricted cash (note 3)			26,888,466			—
	Sales tax recoverable			13,590,640			260,784
	Other current assets (note 4)			1,515,511			54,527
				42,133,963			730,343
	Non-current assets
	Restricted cash (note 3)			—			5,400,000
	Advance payment			19,520,025			—
	Deferred development costs (note 5)			—			32,334,346
	Construction-in-progress (note 5)			625,636,458			—
	Property, plant and equipment - net of accumulated depreciation of $86,934 (2012 - $47,582) (note 6)			115,915			82,188
	Intangible assets - net of accumulated amortization of $592,315 (2012 - $385,980) (note 7)			430,584			82,388
	Deferred financing costs - net of accumulated amortization of $1,056,079 (2012 - $nil)			19,361,860			—
	Derivative assets (note 12)			26,757,264			—
			$	733,956,069		$	38,629,265
	Liabilities
	Current liabilities
	Accounts payable and accrued liabilities		$	43,155,372		$	712,771
	Current portion of construction facility loan (note 9)			1,914,367			—
	Current portion of long-term contingent liabilities (note 14)			1,564,600			1,346,000
	Derivative liability - current portion (note 12)			7,814,992			—
	Other current liabilities (note 8)			1,030,657			—
				55,479,988			2,058,771
	Non-current liabilities
	Construction facility loan (note 9)			542,717,827			—
	Long-term contingent liabilities (note 14)			9,500,000			1,064,600
	Asset retirement obligation (note 11)			5,833,484			—
				613,531,299			3,123,371
	Partners’ capital
	Contributions (note 10)			103,164,191			35,440,000
	Accumulated net income			17,260,579			65,894
				120,424,770			35,505,894
			$	733,956,069		$	38,629,265
	South Kent Wind LP
Statement of Operations and Comprehensive Income
For the year ended December 31, 2013
(expressed in Canadian dollars)
		2013			2012			2011
Revenue		$	—		$	—		$	—
Operating expenses
Professional fees			(341,110	)		—			—
General and administrative			(320,281	)		(27,048	)		—
General and administrative - related party			(555,588	)		—			—
Depreciation and amortization			(32,863	)		—			—
Operating loss			(1,249,842	)		(27,048	)		—
Unrealized gain on derivatives (note 12)			18,942,272			—			—
Other (expenses) income			(497,745	)		92,942			—
Net income and comprehensive income		$	17,194,685		$	65,894		$	—
South Kent Wind LP
Statement of Changes in Partners’ Capital
For the year ended December 31, 2013
(expressed in Canadian dollars)
		Partners’			Accumulated			Total
		capital			net income
Balance at January 1, 2011		$	—		$	—		$	—
Cash initial contribution			10,000			—			10,000
Cash contribution			22,410,000			—			22,410,000
Net income			—			—			—
Balance at December 31, 2011		$	22,420,000		$	—		$	22,420,000
Cash contribution			13,020,000			—			13,020,000
Net income			—			65,894			65,894
Balance at December 31, 2012		$	35,440,000		$	65,894		$	35,505,894
Cash contribution			9,016,022			—			9,016,022
Cash distribution			(21,393,091	)		—			(21,393,091	)
Non-cash contribution			80,101,260			—			80,101,260
Net income			—			17,194,685			17,194,685
Balance at December 31, 2013		$	103,164,191		$	17,260,579		$	120,424,770
South Kent Wind LP
Statements of Cash Flows
For the year ended December 31, 2013
(expressed in Canadian dollars)
		2013			2012			2011
Operating activities
Net income (loss) for the period		$	17,194,685		$	65,894		$	—
Adjustment to reconcile net income (loss) to net cash used in operating activities
Unrealized gain on derivatives			(18,942,272	)		—			—
Non-cash activities			100,879			(38,984	)		—
Bad debt expense			300,000			—			—
			(1,346,708	)		26,910			—
Investing activities
Consideration paid for the acquisition of project assets			(1,346,000	)		—			(15,215,910	)
Construction costs paid			(478,425,665	)		—			—
Purchase of property, plant and equipment and intangible assets			(627,610	)		(178,184	)		(162,482	)
Deferred development costs paid			—			(12,748,484	)		(1,346,818	)
Payment for restricted cash			(21,488,466	)		—			(5,400,000	)
			(501,887,741	)		(12,926,668	)		(22,125,210	)
Financing activities
Partner contribution			9,016,022			—			—
Construction facility loan proceeds			535,753,771			—			—
Deferred financing costs paid			(20,417,939	)		—			—
Distribution to partners			(21,393,091	)		13,020,000			22,420,000
			502,958,763			13,020,000			22,420,000
Increase (decrease) in cash and cash equivalents during the period			(275,686	)		120,242			294,790
Cash and cash equivalents - Beginning of period			415,032			294,790			—
Cash and cash equivalents - End of period		$	139,346		$	415,032		$	294,790
Supplemental non-cash activities disclosure
Transfer to Construction-in-progress from deferred development costs		$	32,334,346		$	—		$	—
Accrued construction costs		$	42,442,601		$	—		$	—
Non-monetary contribution from partners		$	80,101,260		$	—		$	—
Construction loan - capitalized interest		$	8,878,422		$	—		$	—
Depreciation and amortization		$	1,200,887		$	257,093		$	176,469
Community fund commitment		$	10,000,000		$	—		$	—
South Kent Wind LP
Notes to Financial Statements
December 31, 2013
(expressed in Canadian dollars)
1	General information
The Partnership
South Kent Wind LP (the Partnership), a limited partnership under the laws of the Province of Ontario, was formed on January 10, 2011, as a joint venture project between Samsung Renewable Energy Inc. (Samsung) and Pattern South Kent LP Holdings LP, a subsidiary of Pattern Renewable Holdings Canada ULC (PRHC), each as 49.99% limited partners of the Partnership, and South Kent Wind GP Inc. (the GP), as the 0.02% general partner of the Partnership. The terms of the Partnership initially were governed by the Limited Partnership Agreement of the Partnership, dated January 10, 2011, which was subsequently superseded in its entirety by the Amended and Restated Limited Partnership Agreement of the Partnership, dated February 22, 2013. The Partnership was created to develop, build and operate a wind power project in the Regional Municipality of Chatham-Kent that is expected to generate 270 megawatts (MW) of power (the Project). The Project is part of Phase 1 of the Green Energy Investment Agreement that Samsung C&T Corp., a parent company of Samsung, entered into with the Government of Ontario in January 2010, subsequently amended in June 20, 2013.
On February 24, 2013, Samsung transferred its LP interest in the Partnership to SRE SKW LP Holdings LP, an affiliate of Samsung.
On October 2, 2013, in a series of transactions: (i) Pattern South Kent GP Holdings Inc., a wholly owned subsidiary of PRHC, transferred all of the general partner interests in Pattern South Kent LP Holdings LP to PRHC, causing Pattern South Kent LP Holdings LP to be dissolved by operation of law and PRHC to acquire the LP interests in the Partnership that previously were held by Pattern South Kent LP Holdings LP; (ii) PRHC transferred its LP interest in the Partnership and its ownership interest in Pattern South Kent GP Holdings Inc., which owned PRHC’s ownership interest in the GP, to Pattern Canada Operations Holdings ULC, an affiliate of Pattern Energy Group Inc. (Pattern); and (iii) Pattern South Kent GP Holdings Inc. was dissolved, so that Pattern Canada Operations Holdings ULC now holds Pattern’s (a) LP interests in the Partnership and (b) ownership interests in the GP.
The Partnership is controlled by its general partner, the GP, also a joint venture controlled by affiliates of Samsung and Pattern. The GP is governed by the Amended and Restated Unanimous Shareholder Agreement of the GP, dated March 6, 2013 (the Shareholder Agreement). As at December 31, 2013 and 2012, the Partnership’s ownership interests were distributed as follows:
		2013			2012
SRE SKW LP Holdings LP			49.99%			—  %
Pattern Canada Operations Holdings ULC			49.99%			—  %
Samsung Renewable Energy Inc.			—  %			49.99%
Pattern South Kent LP Holdings LP			—  %			49.99%
South Kent Wind GP Inc.			0.02%			0.02%
			100.00%			100.00%
The Project
The Project is a 270 MW wind project consisting of 124 Siemens wind turbine generators located in the Regional Municipality of Chatham-Kent, Ontario.
On August 2, 2011, the Partnership entered into a power purchase agreement (PPA) with the Ontario Power Authority (OPA) related to the sale of 100% of the electrical output of the Project at prescribed electricity rates for a period of 20 years following Commercial Operation Date (COD), which is expected to be in the second quarter of 2014 (note 14).
On June 15, 2012, the Project received the final approval in the permitting process, known as the Renewable Energy Approval process. On December 5, 2012, decisions by the Environmental Review Tribunal on all appeals were made in favour of the Project. The Partnership secured sufficient land rights and commitments to construct the Project, including turbine locations, roads, collector system, substation and the transmission line.
2	Summary of significant accounting policies
The principal accounting policies applied in the preparation of these financial statements are set out below. These policies have been consistently applied to the period presented, unless otherwise stated.
Basis of preparation
The accompanying financial statements are presented using accounting principles generally accepted in the United States of America (U.S. GAAP). The preparation of U.S. GAAP financial statements requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Because the use of estimates is inherent in the financial reporting process, actual results could differ from those estimates.
In recording transactions and balances resulting from business operations, the Partnership uses estimates based on the best information available. Estimates are used for such items as asset retirement obligation valuation of derivative contracts and acquisition contingencies.
These financial statements do not include assets, liabilities, revenue and expenses of the GP and limited partners. The financial statements of the Partnership reflect no provision or liability for income taxes because profits and losses of the Partnership are allocated to the partners and are included in the income tax returns of partners. Income and losses for tax purposes may differ from the financial statement amounts and the partners’ capital reflected in the financial statements does not necessarily reflect their tax basis.
Functional and presentation currency
Items included in the financial statements of the Partnership are measured using the currency of the primary economic environment in which the Partnership operates (the functional currency). The financial statements are presented in Canadian dollars, which is the Partnership’s functional and presentation currency.
Fair value of financial instruments
ASC 820, Fair Value Measurements, defines fair value as the price at which an asset could be exchanged or a liability transferred in an orderly transaction between knowledgeable, willing parties in the principal or most advantageous market for the asset or liability. Where available, fair value is based on observable market prices or derived from such prices. Where observable prices or inputs are not available, valuation models are applied. These valuation techniques involve some level of management estimation and judgment, the degree of which is dependent on the price transparency for the instruments or market and the instruments’ complexity.
Cash and cash equivalents
Cash and cash equivalents include cash on hand, deposits held at call with banks and other short-term highly liquid investments with original maturities of three months or less.
Restricted cash
Restricted cash consists of cash balances required to collateralize commercial bank letter of credit facilities related primarily to interconnect rights and power purchase agreements (PPAs) and for reserves required under the Partnership’s loan agreements (note 3).
Concentration of credit risk
Financial instruments that potentially subject the Partnership to concentrations of credit risk consist primarily of cash and cash equivalents and restricted cash. The Partnership places its cash and cash equivalents and restricted cash with high-quality institutions.
Deferred development costs
The Partnership developed and is now constructing a wind power plant for its own use. There are two phases to the development of the wind power plant: first, a feasibility stage where all costs are expensed; and second, a construction phase where capitalization is appropriate, subject to the appropriate criteria (note 5).
Judgment needs to be exercised for each situation. The Partnership determines whether or not the wind power plant can be built to its proposed specifications and in compliance with the respective regulations. During the feasibility stage, it is uncertain whether the wind power plant will be completed and whether future economic benefits will flow to the Partnership. During the development stage, the Partnership will build the wind power plants. It can reliably measure the cost of development and it is probable that future economic benefits will flow to the Partnership. Certain costs incurred during the development stage should be recognized as an item of deferred development costs.
An evaluation of the circumstances surrounding the development of the Project and in particular the provisions of the Green Energy Investment Agreement, which provide for the issuance of a PPA and support through the permitting process, support the conclusion that the Project moved beyond the feasibility stage prior to the date of inception of the Partnership. Accordingly, all development costs have been capitalized.
Other development expenditures that do not meet the criteria are recognized as an expense when incurred. Development costs previously recognized as an expense are not recognized as an asset in a subsequent period.
Development costs of $32,334,346 incurred during the development stage including $17,369,038 of asset acquired costs through the asset purchase agreements (APA), which had been capitalized and recorded as deferred development costs in the statement of financial position, were transferred and recorded as construction-in-progress as the construction commenced on March 8, 2013.
Construction-in-progress
Construction-in-progress represents the accumulated costs of projects in construction. Construction costs include turbines for which the Partnership has taken legal title, civil engineering, electrical and other related costs. Other capitalized costs include reclassified deferred development costs, amortization of intangible assets, amortization of deferred financing costs, capitalized interest and other costs required to place a project into commercial operation. Construction-in-progress is reclassified to property, plant and equipment when the project begins commercial operations.
Advance payments
Advance payments represent amounts advanced to turbine and other suppliers for the manufacture of wind turbines and other plant assets in accordance with supply agreements for the Partnership’s wind power project and for which the Project has not taken title. Advance payments are reclassified to Construction-in-progress when the Partnership takes legal title to the related turbines and other plant assets and they are reclassified to property, plant and equipment when the project achieves commercial operation. Depreciation does not commence until projects enter commercial operation and assets are placed in service.
Property, plant and equipment
Property, plant and equipment are stated at historical cost, less depreciation. Historical cost includes expenditure that is directly attributable to the acquisition of the items.
Asset retirement obligations included in property, plant and equipment are stated at the present value of future cash flows of asset retirement obligations.
Subsequent costs are included in the asset’s carrying value or recognized as separate assets, as appropriate, only when it is probable the future economic benefits associated with the item will flow to the Partnership and the cost of the item can be measured reliably.
Depreciation on property, plant and equipment is calculated using the straight-line method to allocate their cost to their residual values over their estimated useful lives. The assets’ residual values and useful lives are reviewed and adjusted, if appropriate, at the end of each reporting period.
Intangible assets (lease options)
Lease options are recognized at fair value at the acquisition date and subsequently accounted for at cost. Lease options have a finite useful life and are carried at cost less accumulated amortization. Amortization is calculated using the straight-line method to allocate the cost of lease options over the period of expected future benefit (i.e., the contract period of each lease option). Separately acquired lease options are capitalized on the basis of the costs incurred to enter into the respective contract considering legal fees and service fees.
Impairment of long-lived assets
The Partnership periodically evaluates whether events have occurred that would require revision of the remaining useful life of equipment and improvements and purchased intangible assets or render them not recoverable. If such circumstances arise, the Partnership uses an estimate of the undiscounted value of expected future operating cash flows to determine whether the long-lived assets are impaired. If the aggregate undiscounted cash flows are less than the carrying amount of the assets, the resulting impairment charge to be recorded is calculated based on the excess of the carrying value of the assets over the fair value of such assets, with the fair value determined based on an estimate of discounted future cash flows.
Interest capitalization
The Partnership capitalizes interest and related financing fees from non-recourse debt used to finance projects in construction. Capitalization is discontinued when a project goes into commercial operation.
Derivatives
The Partnership recognizes its derivative instruments as either assets or liabilities in the statement of financial position at fair value. The accounting for changes in the fair value (i.e., gains or losses) of a derivative instrument depends on whether it qualifies and has been designated as part of a hedging relationship and, further, on the type of hedging relationship.
For derivative instruments that are designated and qualify as a cash flow hedge (i.e., hedging the exposure to variability in expected future cash flows that are attributable to a particular risk), the effective portion of the gain or loss on the derivative instrument is reported as a component of other comprehensive income (OCI). Changes in the fair value of these derivatives are subsequently reclassified into earnings in the period the hedged transaction affects earnings. The ineffective portion of changes in fair value is recorded as a component of net income in the statement of comprehensive income.
For undesignated derivative instruments, their change in fair value is reported as a component of net income in the statement of operations and comprehensive income.
The Partnership enters into derivative transactions for the purpose of reducing exposure to fluctuations in interest rates. The Partnership entered into interest rate swaps. Interest rate swaps are instruments used to fix the interest rate on variable interest rate debt.
Deferred financing costs
Financing costs incurred in connection with obtaining construction and term financing, which include direct financing, legal and other upfront costs of borrowing, are deferred and amortized over the lives of the respective loans using the effective-interest method. Amortization of deferred financing costs is capitalized during construction or expensed following commencement of commercial operation.
Accounts payable and other accrued liabilities
Trade payables are obligations to pay for goods or services that have been acquired in the ordinary course of business from suppliers. Payables with payment terms extended beyond one year from the statement of financial position date are presented as non-current liabilities.
Contingent liabilities
Contingent liabilities for environmental restoration, restructuring costs and other legal obligations are recognized when: the Partnership has a present legal obligation as a result of past events; it is probable that an outflow of resources will be required to settle the obligation; and the amount has been reasonably estimated.
Asset retirement obligation
The Partnership records an asset retirement obligation for the estimated costs of decommissioning turbines, removing above-ground installations and restoring sites, at the time when a contractual decommissioning obligation materializes. The Partnership records accretion expense, which represents the increase in the asset retirement obligation, over the remaining life of the associated wind project. Accretion expense is recorded as cost of revenue in the statement of comprehensive income using accretion rates based on credit adjusted risk free interest rates of 5.54%.
Comprehensive income
Comprehensive income consists of net income and other comprehensive income.
Contributions
Contributions from joint venture partners are classified as equity.
3	Restricted cash
The following table presents the components of restricted cash:
		December 31,
		2013			2012
Security deposit for letter of guarantee to OPA		$	8,100,000		$	5,400,000
Security deposit for letter of guarantee to Municipality of Chatham-Kent			2,614,000			—
Security deposit for letter of guarantee - others			82,338			—
10% holdback account for contractors			16,092,128			—
		$	26,888,466		$	5,400,000
The Partnership maintains term deposits with Korea Exchange Bank of Canada that are restricted as security for the letter of guarantee to the OPA, and provided as the initial and incremental security under the PPA. The Partnership classifies these balances as restricted cash in current assets in the statement of financial position as the restrictions are anticipated to be released on COD of the Project, which is expected to be in the second quarter of 2014 (note 2).
4	Other current assets
The following table presents the components of other current assets:
		December 31,
		2013			2012
Mortgage debt receivable, net of bad debt provision of $300,000		$	828,386		$	—
Refundable deposit on COD			86,000			—
Prepaid expenses			484,477			15,544
Accrued interest income			116,648			38,983
		$	1,515,511		$	54,527
5	Deferred development costs and construction-in-progress
The following table presents the components of deferred development costs and construction-in-progress:
		December 31,
		2013			2012
Deferred development costs		$	—		$	32,334,346
Construction-in-progress		$	625,636,458		$	—
Deferred development costs of $32,334,346 incurred were transferred to construction-in-progress on March 8, 2013, the date the project commenced construction.
Construction-in-progress includes capitalized interest expense of $12,583,514 and $nil as of December 31, 2013 and 2012, respectively.
6	Property, plant and equipment
The following table reflects the categories within property, plant and equipment at historical cost:
		December 31,						Depreciable
		2013			2012			life (years)
Machinery and equipment		$	202,849		$	129,770			5
Subtotal			202,849			129,770
Less: Accumulated depreciation			(86,934	)		(47,582	)
		$	115,915		$	82,188
Depreciation expense of $6,489 (2012 - $47,582) has been charged to deferred development costs in the statement of financial position and $32,863 (2012 - $nil) has been charged to the statement of operations and comprehensive income.
7	Intangible assets
		2013			2012
Beginning net book value		$	82,388		$	135,343
Additions			554,531			178,184
Amortization expense			(206,335	)		(231,139	)
Closing net book value		$	430,584		$	82,388
Cost		$	1,022,899		$	468,368
Accumulated amortization			(592,315	)		(385,980	)
Net book value		$	430,584		$	82,388
Amortization of $206,355 (2012 -$231,139) is included in deferred development costs in the statements of financial position.
8	Other current liabilities
The following table presents the components of accounts payable and other accrued liabilities:
		December 31,
		2013			2012
Accrued expenses		$	856,084		$	—
Accrued interest - construction facility loan			174,573			—
		$	1,030,657		$	—
9	Long-term debt
On March 8, 2013, the Partnership signed a credit facility agreement with a syndicate of lenders consisting of 15 different financial institutions for a term of construction period plus seven years at a rate of Canadian Dealer Offered Rate (CDOR) plus 2.5% per annum for the first four years and CDOR plus 2.75% per annum thereafter. The credit facilities under the agreement include a $683,817,047 construction facility, letter of credit facility and an interest rate hedge facility. The funds from these facilities will be utilized to finance the construction of the Project and to run the project operations thereafter.
For the periods ended December 31, 2013 and December 31, 2012, the credit facilities incurred capitalized interest charges of $8,878,422 and $nil, respectively. Interest payments on the construction facility are currently deferred and will be added to the loan principal on term conversion.
The terms and conditions of outstanding borrowings were as follows:
		December 31,						Interest rate as of						Interest		Loan
								December 31,
		2013			2012			2013			2012			type		type		Maturity
Construction facility loan		$	544,632,194		$	—			3.75	%		—	%		Variable		Project		March 8, 2021
																	financing
Current portion			(1,914,367	)		—
		$	542,717,827		$	—
The following are the amounts due for long-term debt as of December 31, 2013:
2014		$	1,914,367
2015			23,185,104
2016			22,109,351
2017			25,773,416
2018			26,819,083
Thereafter			444,830,873
		$	544,632,194
10	Contributions from/distributions to joint venture partners
		2013
		SRE SKW LP			Pattern			South Kent			Total
		Holdings LP1			Canada			Wind GP
					Operations			Inc.
					Holdings
					ULC2
Balance - Beginning of year		$	17,716,456		$	17,716,456		$	7,088		$	35,440,000
Subsequent cash contribution on
Jan. 3, 2013			1,699,660			1,699,660			680			3,400,000
Jan. 11, 2013			1,449,710			1,449,710			580			2,900,000
Feb. 5, 2013			1,349,730			1,349,730			540			2,700,000
Feb. 22, 2013			—			—			3,943			3,943
Mar. 6, 2013			—			—			11,802			11,802
Mar. 6, 2013			—			—			277			277
			4,499,100			4,499,100			17,822			9,016,022
Subsequent cash distribution
Mar. 7, 2013			(1,126,037	)		(1,126,037	)		(451	)		(2,252,525	)
Mar. 8, 2013			(9,568,369	)		(9,568,369	)		(3,828	)		(19,140,566	)
			(10,694,406	)		(10,694,406	)		(4,279	)		(21,393,091	)
Non-cash contribution - vend in
Feb. 22, 2013			9,856,843			9,856,843			—			19,713,686
Mar. 6, 2013			29,500,000			29,500,000			—			59,000,000
Mar. 7, 2013			693,787			693,787			—			1,387,574
			40,050,630			40,050,630			—			80,101,260
Balance - End of year		$	51,571,780		$	51,571,780		$	20,631		$	103,164,191
1	On February 24, 2013, Samsung Renewable Energy Inc. transferred its ownership interest to SRE SKW LP Holdings LP at fair value, which approximates net book value.
2	On October 2, 2013, Pattern South Kent LP Holdings LP, in a series of transactions, transferred its ownership interest in South Kent Wind LP to Pattern Canada Operations Holdings ULC at fair value, which approximates net book value.
		2012
		SRE SKW LP			Pattern			South Kent			Total
		Holdings LP1			Canada			Wind GP
					Operations			Inc.
					Holdings
					ULC2
Balance - Beginning of year		$	11,207,758		$	11,207,758		$	4,484		$	22,420,000
Subsequent contributions on
May 4, 2012			3,459,308			3,459,308			1,384			6,920,000
August 31, 2012			1,809,638			1,809,638			724			3,620,000
November 20, 2012			439,912			439,912			176			880,000
November 28, 2012			799,840			799,840			320			1,600,000
			6,508,698			6,508,698			2,604			13,020,000
Balance - End of year		$	17,716,456		$	17,716,456		$	7,088		$	35,440,000
Pursuant to an agreement dated February 19, 2013 between the Partnership, Samsung, PRHC and certain of their respective affiliates, certain project development costs in the amount of $19,713,686 incurred by Pattern were contributed to the Partnership. In order to maintain the equal ownership within the Partnership, Samsung acquired an additional interest in the Partnership for consideration payable to PRHC in cash and through exchange of ownership interest in another partnership entity related to both Samsung and PRHC. This transaction has no impact on the Partnership.
Pursuant to a series of Assignment and Assumption Agreements dated March 6, 2013 between and/or among Samsung, PRHC, the Partnership, and various affiliates of Samsung and PRHC, a construction deposit of $59,000,000 was placed with an affiliate of Siemens AG by Samsung and Pattern were contributed to the Partnership in accordance with a Memorandum of Understanding (MOU) signed on October 30, 2012 on behalf of the Partnership.
Pursuant to a series of Assignment and Assumption Agreements dated March 6, 2013 between and/or among Samsung, PRHC, the Partnership, and various affiliates of Samsung and PRHC, certain project development costs, which were not part of the previous contribution on February 19, 2013, in the amount of $1,387,574 incurred by Pattern were contributed to the Partnership. Afterward, Samsung acquired additional interest in the Partnership for a cash consideration payable to an affiliate of PRHC. This transaction has no impact on the Partnership.
Prior to financial close, Korea Electric Power Corporation (KEPCO), another party of Korean Consortium of the Green Energy Investment Agreement, is entitled to participate as an equity investor in the Project, where the purchase price shall be equal to the proportionate share of the Project’s fair market value. The interest of the Partnership to be held by KEPCO shall not be greater than 20%. KEPCO’s entitlement to participate in the Project shall expire on achieving financial close of the project financing for construction of the Project. On February 14, 2013, KEPCO abandoned its entitlement to participate in the Project by signing an amending agreement.
11	Asset retirement obligation
The Partnership’s asset retirement obligation represents the estimated cost of decommissioning the turbines, removing above-ground installations and restoring the sites at a date that is 20 years from the commencement of commercial operations.
The following table presents a reconciliation of the beginning and ending aggregate carrying amounts of the asset retirement obligation:
		December 31,
		2013			2012
Asset retirement obligation, beginning balance		$	—		$	—
Additions during the year			5,833,484			—
Accretion expense			—			—
Asset retirement obligation, end of year		$	5,833,484		$	—
12	Derivatives
On March 14, 2013, the Partnership entered into interest rate swaps to manage exposure to interest rate risk on its long-term debt. The interest rate swaps are undesignated derivatives that are used to mitigate exposure to variable interest rate debt by exchanging variable interest rate payments for fixed rate payments of 5.54%.
The following table presents the amounts that are recorded in the Partnership’s statement of financial position as of December 31, 2013:
Undesignated derivative instruments classified as assets (liabilities)
								As of December 31, 2013						For the period ended
								Fair market value						Gain		Gain
														recognized		recognized
Derivative type		Quantity			Maturity			Current			Non-current			into		into
					date			portion			portion			earnings		OCI
Interest rate swaps			13			March 31, 2032		$	(7,814,992	)	$	26,757,264		$	18,942,272	$	—
13	Fair value measurement
The Partnership’s fair value measurements incorporate various factors, including the credit standing and performance risk of the counterparties, the applicable exit market, and specific risks inherent in the instrument. Non-performance and credit risk adjustments on risk management instruments are based on current market inputs when available, such as credit default swap spreads. When such information is not available, internal models are used.
Assets and liabilities recorded at fair value in the financial statements are categorized based on the level of judgment associated with the inputs used to measure their fair value. Hierarchical levels directly related to the amount of subjectivity associated with the inputs to valuation of these assets or liabilities are as follows:
Level 1 - Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date.
Level 2 - Inputs (other than quoted prices included in Level 1) are either directly or indirectly observable for the asset or liability through correlation with market data at the measurement date and for the duration of the instrument’s anticipated life.
Level 3 - Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities and which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model.
Short-term financial instruments consist principally of cash and cash equivalents, restricted cash, accounts payable, current derivative liability and other accrued liabilities. Based on the nature and short maturity of these instruments their fair value is approximated using carrying cost and they are presented in the financial statements at carrying cost.
Long-term debt is presented on the statement of financial position at amortized cost. The fair value of variable interest rate long-term debt is approximated by its carrying cost.
Derivatives are presented in the financial statements at fair value. The interest rate swaps were valued by discounting the net cash flows using the forward CDOR curve with the valuations adjusted by the counterparties’ credit default swap rate.
The following table presents the fair values according to each defined level.
Financial assets and liabilities measured on a recurring basis:
		Level 1			Level 2			Level 3
December 31, 2013
Interest rate swaps		$	—		$	18,942,272		$	—
December 31, 2012
Interest rate swaps		$	—		$	—		$	—
14	Commitments and contingencies
Power purchase agreement
The Partnership entered into a PPA with the OPA on August 2, 2011. The contract capacity of the PPA is defined as 270 MW and the term of the PPA is 20 years from the COD. Under the PPA, the electrical output
from the Project is sold at an electricity price equal to $135 per MWh (on the base date as at September 30, 2009), with 80% of the price fixed and 20% escalating at the Consumer Price Index. The Partnership obtained NTP under the PPA on January 7, 2013. The Partnership has provided to the OPA initial security of $20 per kW of contract capacity. In addition, the Partnership will deliver to the OPA the additional amount of incremental NTP security defined as $10 per kW of contract capacity after receiving the NTP. Both initial and incremental security will be returned to the Partnership after the COD. As at December 31, 2013, the Partnership provided a letter of guarantee amounting to $8,100,000 (2012—$5,400,000) to the OPA, as the initial and incremental security agreed within the PPA. Korea Exchange Bank of Canada issued the letter of guarantee due on July 31, 2014 for the Partnership, based on a restricted term deposit of $8,100,000 (2012 - $5,400,000).
On January 29, 2013 and August 22, 2013, the Partnership amended the PPA by way of an amending agreement with the OPA in connection with announced changes in the market rules governing the dispatch of certain intermittent generators, including those connected to the IESO-controlled grid. Among other provisions, the amendment will limit the amount of economic curtailment to which the Project is subject.
Contingent payment under APA
Per certain Asset Purchase Agreements between the GP, in its capacity as general partner and on behalf of the Partnership, and Northland Power Inc., dated March 4, 2011, and between the GP, in its capacity as general partner of the Partnership, and Suncor Energy Products Inc., dated March 22, 2011, the Partnership is liable to pay $675,000 and $389,600, respectively, once the Project reaches commercial operation under the PPA.
Community Fund Agreement
On April 17, 2013, the GP, in its capacity as general partner and on behalf of the Partnership, entered into a South Kent Wind Community Fund Agreement with Chatham-Kent Community Foundation, in which the Partnership committed to twenty annual contributions of $500,000 plus an initial contribution of $1,000,000 million. In April 2013, the initial $1,000,000 was paid on close of construction financing and recorded as construction-in-progress. The remaining $10,000,000 was recorded as a liability.
Operational Incentive Agreement
On March 8, 2013, an Operational Incentive Agreement was entered into between Samsung, an affiliate of PRHC and Siemens Canada Limited to define operational objectives and the terms and conditions upon which the Partnership may pay operational incentive payments to Siemens for achieving one or more of such operational objectives under the turbine supply agreements of certain projects under development by Samsung and affiliates of PRHC, including the Project. Siemens earned an initial payment of $1,078,996 for having satisfied a Peak Capacity Objective defined under the agreement.
The operational incentive payment shall not exceed any of the applicable maximums of (a) $20 per kW of the agreed de-rated capacity of wind turbines purchased under the TSA for the Project, and (b) an aggregate of $15,000,000 under all TSAs for all projects subject to the Operational Incentive Agreement, including the Project, and the South Kent, K2, and Armow wind projects.
Land Lease Agreement
The Partnership has acquired various lease option agreements with landowners through the APAs, and subsequently the Partnership exercised most of the options to execute lease agreements with landowners during the year.
The lease payment including amortization of lease option in the prior year was capitalized to Construction-in-progress and deferred development costs. The capitalized lease payments and amortization of land options are $713,605 and $177,184 for the years ended December 31, 2013 and 2012, respectively.
The future minimum payments related to these leases as of December 31, 2013 are as follows:
2014		$	1,017,943
2015			1,222,133
2016			1,295,059
2017			1,302,068
2018			1,312,842
Thereafter			39,463,763
Total		$	45,613,807
Other commitments
The Partnership has entered into an agreement to purchase turbine related consumable supplies, components, materials, equipment and items required for the Project. The purchase commitment outstanding for these items at December 31, 2013 is $50,266,877.
The Partnership also has other project related contract, and the contract commitment outstanding at December 31, 2013 is $23,967,910.
15	Related party transactions
The Partnership is controlled by the GP, which is jointly controlled by Samsung and Pattern in accordance with the terms of the Shareholder Agreement. Certain terms of the Samsung Pattern Joint Venture Wind Development Agreement, entered into between Samsung and an affiliate of PRHC on July 27, 2010, directed the responsibilities of Samsung and PRHC during the development of the Project.
The following transactions were carried out with related parties:
	a)	Management, Operation, and Maintenance Agreement (MOMA)
On March 8, 2013, the Partnership entered into MOMA with Pattern Operators Canada ULC, which is 100% owned by an affiliate of Pattern to operate and manage the maintenance of the wind plant and to perform certain other services pertaining to the wind plant in accordance with the terms and conditions set in the MOMA.
The fixed annual fee for the service is $855,000 pro-rated for the period from March 8, 2013 until the COD and thereafter the annual fee will be increased to $1,425,000 until the end of the term (20 years from the COD). The Partnership paid $627,252 during the year, which is capitalized and recorded to construction-in-progress in the statement of financial position.
	b)	Engineering Procurement and Construction Contract (EPC Contract)
On March 8, 2013, the Partnership entered into an EPC contract with SRE SKW EPC LP, which is 100% owned by Samsung, to build the balance of plant. $184,067,045 has been invoiced to the Partnership as of December 31, 2013, which was capitalized and recorded in construction-in-progress in the statements of financial position.
	c)	Project Administration Agreement (PAA)
On March 8, 2013, the Partnership entered into the PAA with SRE Wind PA LP (PA), which is 100% owned by Samsung to supply project administrative services.
The fixed annual fee for the service is $350,000 retroactively pro-rated for the period from June 15, 2012 until the COD and thereafter the annual fee will be increased to $500,000. The Partnership paid $555,588 during the year, which is recorded in the statement of operations and comprehensive income.
	d)	Deferred development costs transferred to the Project by Samsung and PRHC (note 10)
Siemens deposits paid and certain development cost incurred by Samsung and an affiliate of PRHC were transferred to the Partnership at carrying value in March 2013.
		Samsung			PRHC			Total
Siemens deposit		$	29,500,000		$	29,500,000		$	59,000,000
Development costs			—			20,950,417			20,950,417
		$	29,500,000		$	50,450,417		$	79,950,417
	e)	The Partnership recorded the following balances and transactions with related parties:
		2013			2012
Related party payable		$	42,811,950		$	—
Deferred development costs transferred		$	79,450,417		$	—
16	Subsequent events
On January 26, 2014, the Environmental Review Tribunal dismissed a challenge to the Project modifying the position and rated capacity of two turbines.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Principles of Consolidation	'
	Principles of Consolidation
	The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States (U.S. GAAP). They include the results of wholly-owned and partially-owned subsidiaries in which the Company has a controlling interest with all significant intercompany accounts and transactions eliminated.
Use of Estimates	'
	Use of Estimates
	The preparation of financial statements in conformity with U.S. generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates, and such differences may be material to the consolidated financial statements.
Unaudited Pro Forma Income Tax	'
	Unaudited Pro Forma Income Tax
	In order to present the tax effect of the Contribution Transactions, the Company has presented a 2012 pro forma income tax provision as if the Contribution Transactions occurred effective January 1, 2012 and as if the Company were under control of a Subchapter C-Corporation for U.S. federal income tax purposes.
Variable Interest Entities	'
	Variable Interest Entities
	ASC 810, Consolidation of Variable Interest Entities, defines the criteria for determining the existence of Variable Interest Entities (VIEs) and provides guidance for consolidation. The Company consolidates VIEs where the Company is the primary beneficiary. The primary beneficiary of a VIE is the party that has the power to direct the activities that most significantly impact the performance of the entity and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the entity.
	Investments or joint ventures in which the Company does not have a majority ownership interest and are not VIEs for which the Company is considered the primary beneficiary are accounted for using the equity method. These amounts are included in unconsolidated investments in the consolidated balance sheets.
Noncontrolling Interests	'
	Noncontrolling Interests
	Noncontrolling interests represent third-party interests in Gulf Wind which resulted from the sale of a noncontrolling interest to an unrelated third party on September 3, 2010 and the interest retained by Pattern Development in connection with the Contribution Transactions on October 2, 2013. The Company has determined that the operating partnership agreement for Gulf Wind does not allocate economic benefits pro rata to its two classes of investors and the appropriate methodology for calculating the noncontrolling interest balance that reflects the substantive profit sharing arrangement is a balance sheet approach using the hypothetical liquidation at book value (HLBV) method.
	Under the HLBV method, the amounts reported as noncontrolling interest in the consolidated balance sheets and consolidated statements of operations represent the amounts the third party would hypothetically receive at each balance sheet reporting date under the liquidation provisions of the operating partnership agreement assuming the net assets of Gulf Wind were liquidated at recorded amounts determined in accordance with U.S. GAAP and distributed to the investors. The third-party interest in the results of operations of Gulf Wind and the Company’s net income and comprehensive income is determined as the difference in noncontrolling interests in the consolidated balance sheets at the start and end of each reporting period, after taking into account any capital transactions between Gulf Wind and the third party. The noncontrolling interest balance in Gulf Wind is reported as a component of equity in the consolidated balance sheets.
Foreign Currency Translation	'
	Foreign Currency Translation
	The assets and liabilities of foreign subsidiaries, where the local currency is the functional currency, are translated from their respective functional currencies into U.S. dollars at the rates in effect at the balance sheet date, with resulting foreign currency translation adjustments recorded in other comprehensive income (loss), net of tax in the accompanying consolidated statements of stockholders’ equity and comprehensive income (loss). Revenue and expense amounts are translated at average rates during the period. Where the U.S. dollar is the functional currency, translation adjustments are recorded in other income, net in the accompanying consolidated statements of operations.
	Gains and losses realized from transactions, including related party balances not considered permanent investments, denominated in currencies other than an entity’s functional currency are included in other income, net in the accompanying consolidated statements of operations.
Concentrations of Credit Risk	'
	Concentrations of Credit Risk
	Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents, trade receivables and derivative assets. The Company places its cash and cash equivalents with high quality institutions.
	The Company sells electricity and environmental attributes, including renewable energy credits, primarily to creditworthy utilities under long-term, fixed-priced PPAs. The table below presents significant customers who accounted for the following percentages of total revenues:
		Year ended December 31,
		2013			2012			2011
	Manitoba Hydro		17.62	%		32.06	%		20.91	%
	San Diego Gas & Electric		17.23	%		0.18	%		0	%
	Pacific Gas & Electric Company		14.54	%		23.12	%		20.67	%
	Electric Reliability Council of Texas		12.24	%		18.28	%		35.23	%
	The Company’s derivative assets are placed with counterparties that are creditworthy institutions. A derivative asset was generated from Credit Suisse Energy LLC, the counterparty to a 10-year fixed-for-floating swap related to annual electricity generation at the Company’s Gulf Wind project. The Company’s reimbursements for prepaid interconnect network upgrades are with large creditworthy utility companies.
Fair Value of Financial Instruments	'
	Fair Value of Financial Instruments
	ASC 820, Fair Value Measurements, defines fair value as the price at which an asset could be exchanged or a liability transferred in an orderly transaction between knowledgeable, willing parties in the principal or most advantageous market for the asset or liability. Where available, fair value is based on observable market prices or derived from such prices. Where observable prices or inputs are not available, valuation models are applied. These valuation techniques involve some level of management estimation and judgment, the degree of which is dependent on the price transparency for the instruments or market and the instruments’ complexity. See Note 12 on Fair Value Measurements.
U.S. Treasury Grants	'
	U.S. Treasury Grants
	The Company received U.S. Treasury grants on certain wind power projects as defined under Section 1603 of the American Recovery and Reinvestment Act of 2009, as amended by the Tax Relief Unemployment Insurance Reauthorization and Job Creation Act of December 2010, upon approval by the U.S. Treasury Department. The Company records the U.S. Treasury grant proceeds as a deduction from the carrying amount of the related asset which results in a reduction of depreciation expense over the life of the asset. The Company records a catch-up adjustment in the period in which the grant is approved to recognize the portion of the grant that proportionally matches the depreciation for the period between the date of placement in service of the wind power project and approval by the U.S. Treasury Department. See Note 5 on Property, Plant and Equipment.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents
	Cash and cash equivalents consist of all cash balances and highly-liquid investments with original maturities of three months or less. The Company maintains cash and cash equivalents, which consist principally of demand deposits with high credit quality financial institutions. The Company has exposure to credit risk to the extent cash and cash equivalent balances, including restricted cash, exceed amounts covered by federal deposit insurance. The Company believes that its credit risk is immaterial.
Restricted Cash	'
	Restricted Cash
	Restricted cash consists of cash balances which are restricted as to withdrawal or usage and include cash to collateralize bank letters of credit related primarily to interconnection rights and power purchase agreements (“PPAs”) and for certain reserves required under the Company’s loan agreements.
Trade Receivables	'
	Trade Receivables
	The Company’s trade receivables are generated by selling energy and renewable energy credits in the California, Texas, Nevada, Manitoba (Canada) and Puerto Rico energy markets. The Company believes that all amounts are collectible and an allowance for doubtful accounts is not required as of December 31, 2013 and 2012.
Reimbursable Interconnect Costs	'
	Reimbursable Interconnect Costs
	During 2013 and 2012, the Company paid to construct interconnect network upgrades for one of its utility customers. The utility owns the interconnect upgrades and reimbursed the Company with interest when the project reached commercial operations in 2013.
Turbine Advances	'
	Turbine Advances
	Turbine advances represent amounts advanced to turbine suppliers for the manufacture of wind turbines in accordance with turbine supply agreements for the Company’s wind power projects and for which the Company has not taken title. Turbine advances are reclassified to construction in progress when the Company takes legal title to the related turbines and are reclassified to property, plant and equipment when the project achieves commercial operation. Depreciation does not commence until projects enter commercial operation and assets are placed in service.
Deferred Development Costs	'
	Deferred Development Costs
	Deferred development costs consist primarily of initial permitting, environmental reviews, land rights and obligations and preliminary design and engineering work. The Company expenses all project development costs until a project is determined to be technically feasible and likely to achieve commercial success. Capitalized deferred project development costs are reclassified to construction in progress upon start of construction and recorded to property, plant and equipment upon commercial operation.
Construction in Progress	'
	Construction in Progress
	Construction in progress represents the accumulated costs of projects in construction. Construction costs include turbines for which the Company has taken legal title, civil engineering, electrical and other related costs. Other capitalized costs include reclassified deferred development costs, amortization of intangible assets, amortization of deferred financing costs, capitalized interest and other costs required to place a project into commercial operation. Construction in progress is reclassified to property, plant and equipment when the project begins commercial operation.
Property, Plant and Equipment	'
	Property, Plant and Equipment
	Property, plant and equipment represents the costs of completed and operational projects transferred from construction in progress as well as land, computer equipment and software, furniture and fixtures, leasehold improvements and other equipment. Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is calculated using the straight-line method over the assets’ useful lives. Wind farms are depreciated over twenty years and the remaining assets are depreciated over three to five years. Land is not depreciated. Improvements to property, plant and equipment deemed to extend the useful economic life of an asset are capitalized. Repair and maintenance costs are expensed as incurred.
Accounting for Impairment of Long-Lived Assets	'
	Accounting for Impairment of Long-Lived Assets
	The Company periodically evaluates whether events have occurred that would require revision of the remaining useful life of equipment and improvements and purchased intangible assets or render them not recoverable. If such circumstances arise, the Company uses an estimate of the undiscounted value of expected future operating cash flows to determine whether the long-lived assets are impaired. If the aggregate undiscounted cash flows are less than the carrying amount of the assets, the resulting impairment charge to be recorded is calculated based on the excess of the carrying value of the assets over the fair value of such assets, with the fair value determined based on an estimate of discounted future cash flows. Through December 31, 2013, no impairment charges have been recorded.
Derivatives	'
	Derivatives
	The Company recognizes its derivative instruments as assets or liabilities at fair value in the consolidated balance sheets. Accounting for changes in the fair value (i.e., gains or losses) of a derivative instrument depends on whether it has been designated as part of a hedging relationship and on the type of hedging relationship.
	For derivative instruments that are designated as cash flow hedges the effective portion of change in fair value of the derivative is reported as a component of other comprehensive income (loss) (“OCI”). Changes in the fair value of these derivatives are subsequently reclassified into earnings in the period that the hedged transaction affects earnings. The ineffective portion of change in fair value is recorded as a component of net income (loss) on the consolidated statement of operations.
	For undesignated derivative instruments their change in fair value is reported as a component of net income on the consolidated statement of operations.
	The Company enters into derivative transactions for the purpose of reducing exposure to fluctuations in interest rates and electricity prices. The Company has entered into interest rate swaps, an interest rate cap and an electricity price derivative.
	Interest rate swaps are instruments used to fix the interest rate on variable interest rate debt. The Company entered into interest rate swaps in 2013, 2012 and 2011.
	An interest rate cap is an instrument that is used to reduce exposure to future variable interest rates when the related debt is expected to be refinanced. The Company entered into an interest rate cap in 2010. The cap remains in place as of December 31, 2013.
	The Company entered into an electricity price arrangement, which qualifies as a derivative, that fixes the price of approximately 58% of the electricity expected to be produced and sold by Gulf Wind through April 2019, and which reduces the Company’s exposure to spot electricity prices.
Deferred Financing Costs	'
	Deferred Financing Costs
	Financing costs incurred in connection with obtaining construction and term financing are deferred and amortized over the lives of the respective loans using the effective-interest method. Amortization of deferred financing costs is capitalized during construction and recorded as interest expense in the consolidated statements of operations following commencement of commercial operation.
Income Taxes	'
	Income Taxes
	Prior to October 2, 2013, the Company’s predecessor did not provide for income taxes as it was treated as a pass-through entity for U.S. federal and state income tax purposes, except for several specific circumstances involving its Canadian entities, which are subject to Canadian income taxes, its Chilean entities, which are subject to Chilean income taxes, a U.S. entity that is subject to Puerto Rican taxes and a U.S. entity which became subject to U.S. income taxes in 2012. Federal and state income taxes were assessed at the owner level and each owner was liable for its own tax payments. Certain consolidated entities are corporations or have elected to be taxed as corporations. In these circumstances, income tax was accounted for under the asset and liability method.
	Subsequent to October 2, 2013, following the Contribution Transactions, the Company accounts for income taxes under the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been included in the financial statements. Under this method, deferred tax assets and liabilities are determined on the basis of the differences between the financial statement and tax bases of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. The Company recognizes deferred tax assets to the extent that it believes these assets are more likely than not to be realized. In making such a determination, the Company considers all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning and results of recent operations. If the Company determines that it would be able to realize its deferred tax assets in the future in excess of their net recorded amount, it would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes. The Company records uncertain tax positions in accordance with ASC 740 on the basis of a two-step process whereby (1) it determines whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, it recognizes the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority. The Company has a policy to classify interest and penalties associated with uncertain tax positions together with the related liability, and the expenses incurred related to such accruals, if any, are included in the provision for income taxes.
Contingent Liabilities	'
	Contingent Liabilities
	The Company’s contingent liabilities represent deferred and contingent purchase price obligations related to projects acquired through business combinations and are recorded at fair value at each reporting date.
Asset Retirement Obligation	'
	Asset Retirement Obligation
	The Company records asset retirement obligations for the estimated costs of decommissioning turbines, removing above-ground installations and restoring sites, at the time when a contractual decommissioning obligation materializes. The Company records accretion expense, which represents the increase in the asset retirement obligations, over the remaining or operational life of the associated wind project. Accretion expense is recorded as cost of revenue in the statement of operations using accretion rates based on credit adjusted risk free interest rates.
Revenue Recognition	'
	Revenue Recognition
	The Company sells the electricity it generates under the terms of PPAs or at spot market prices. Revenue is recognized based upon the amount of electricity delivered at rates specified under the contracts, assuming all other revenue recognition criteria are met. The Company evaluates its PPAs to determine whether they are in substance leases or derivatives and, if applicable, recognizes revenue pursuant to ASC 840 Leases and ASC 815 Derivatives and Hedging, respectively. As of December 31, 2013, there were no PPAs that are accounted for as leases or derivatives and revenue is recognized on an accrual basis.
	The Company also generates renewable energy credits as it produces electricity. Certain of these energy credits are sold independently in an open market and revenue is recognized at the time title to the energy credits is transferred to the buyer.
	The Company acquired a ten-year energy derivative instrument as part of its acquisition of Gulf Wind in 2010, which fixes approximately 58% of the Project’s expected electricity generation through April 2019. The energy derivative instrument reduces exposure to changes in commodity prices by allowing the Company to lock in a fixed price per MWh for a specified amount of annual electricity generation. The monthly settlement amounts under the energy hedge are accounted for as energy derivative settlements in the consolidated statements of operations. The change in the fair value of the energy hedge is classified as unrealized (loss) gain on energy derivative revenue in the consolidated statements of operations.
	The Company recognizes revenue for warranty settlements and liquidated damages from turbine manufacturers in other revenue upon resolution of outstanding contingencies. Any cash receipts for amounts subject to future adjustment or repayment are deferred in other liabilities until the final settlement amount is considered fixed and determinable.
Cost of Revenue	'
	Cost of Revenue
	The Company’s cost of revenue is comprised of direct costs of operating and maintaining its wind project facilities, including labor, turbine service arrangements, land lease royalties, depreciation, accretion, property taxes and insurance.
Stock-Based Compensation	'
	Stock-Based Compensation
	The Company accounts for stock-based compensation related to stock options granted to employees by estimating the fair value of the stock-based awards using the Black-Scholes option-pricing model. The fair value of the stock options granted are amortized over the applicable vesting period. The Black-Scholes option pricing model includes assumptions regarding dividend yields, expected volatility, expected option term, expected forfeiture rate and risk-free interest rates. The Company estimates expected volatility based on the historical volatility of comparable publicly traded companies for a period that is equal to the expected term of the options. The risk-free interest rate is based on the U.S. treasury yield curve in effect at the time of grant for a period commensurate with the estimated expected life. The expected term of options granted is derived using the “simplified” method as allowed under the provisions of the ASC 718, Compensation—Stock Compensation, and represents the period of time that options granted are expected to be outstanding.
	The Company accounts for stock-based compensation related to restricted stock award grants by amortizing the fair value of the restricted stock award grants, which is the grant date market price, over the applicable vesting period.
	Stock-based compensation expense is recorded as a component of general and administrative expenses in the Company’s consolidated statements of operations.
Comprehensive Income (Loss)	'
	Comprehensive Income (Loss)
	Comprehensive income (loss) consists of net income (loss) and other comprehensive income (loss), net of tax. Other comprehensive income (loss), net of tax included in accumulated other comprehensive income (loss) in the accompanying consolidated statements of stockholders’ equity, is comprised of changes in foreign currency translation adjustments and changes in the fair value of derivatives designated as hedges.
Segment Data	'
	Segment Data
	Operating segments are defined as components of a company about which separate financial information is available that is evaluated regularly by the chief operating decision maker in deciding how to allocate resources and in assessing performance. The Company’s chief operating decision maker is the chief executive officer. Based on the financial information presented to and reviewed by the chief operating decision maker in deciding how to allocate the resources and in assessing the Company’s performance, the Company has determined its wind projects represent individual operating segments with similar economic characteristics that meet the criteria for aggregation into a single reporting segment for financial statement purposes.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Accounting Policies [Abstract]	'
Schedule of Percentages of Total Revenues from Significant Customers	'
	The table below presents significant customers who accounted for the following percentages of total revenues:
		Year ended December 31,
		2013			2012			2011
	Manitoba Hydro		17.62	%		32.06	%		20.91	%
	San Diego Gas & Electric		17.23	%		0.18	%		0	%
	Pacific Gas & Electric Company		14.54	%		23.12	%		20.67	%
	Electric Reliability Council of Texas		12.24	%		18.28	%		35.23	%

Prepaid_Expenses_and_Other_Cur1

Prepaid Expenses and Other Current Assets (Tables)	12 Months Ended
	Dec. 31, 2013
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]	'
Components of Prepaid Expenses and Other Current Assets	'
	The following table presents the components of prepaid expenses and other current assets (in thousands):
		December 31,
		2013		2012
	Prepaid expenses	$	10,132	$	7,202
	Sales tax		50		3,275
	Interconnection network upgrade receivable		2,512		1,854
	Other current assets		1,233		1,463
	Prepaid expenses and other current assets	$	13,927	$	13,794

Property_Plant_and_Equipment_T

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2013
Property Plant And Equipment [Abstract]	'
Schedule of Property, Plant and Equipment	'
	The following presents the categories within property, plant and equipment (in thousands):
		December 31,
		2013			2012
	Operating wind farms	$	1,652,119		$	1,765,200
	Furniture, fixtures and equipment		3,785			3,333
	Land		16			16
	Subtotal		1,655,920			1,768,549
	Less: accumulated depreciation		(179,778	)		(100,247	)
		$	1,476,142		$	1,668,302

Unconsolidated_Investments_Tab

Unconsolidated Investments (Tables)	12 Months Ended
	Dec. 31, 2013
Equity Method Investments And Joint Ventures [Abstract]	'
Schedule of Projects Accounted under Equity Method of Accounting	'
	The following presents projects that are accounted for under the equity method of accounting (in thousands):
							Percentage of Ownership
		December 31,					December 31,
		2013			2012		2013			2012
	South Kent	$	59,488		$	17,895		50	%		50	%
	El Arrayán		21,103			18,323		31.5	%		31.5	%
	Grand		26,464			—		45	%		N/A
	Unconsolidated investments	$	107,055		$	36,218
Summary of Aggregated Balance Sheets and Operating Results of Unconsolidated Joint Ventures	'
	The following summarizes the aggregated balance sheets as of December 31, 2013 and 2012, and operating results of the unconsolidated joint ventures for the years ended December 31, 2013, 2012 and 2011, respectively (in thousands):
		December 31,
		2013			2012
	Current assets	$	78,906		$	33,578
	Non-current assets		1,097,018			142,522
	Total assets	$	1,175,924		$	176,100
	Current liabilities	$	128,076		$	5,153
	Non-current liabilities		810,936			71,709
	Total liabilities	$	939,012		$	76,862
	Total equity	$	236,912		$	99,238
	Total liabilities and equity	$	1,175,924		$	176,100
		Year ended December 31,
		2013			2012		2011
	Revenue	$	—		$	—	$	—
	Other (income) expense		(13,322	)		275		455
	Net income (loss)	$	13,322			$  (275)		$  (455)

Accounts_Payable_and_Other_Acc1

Accounts Payable and Other Accrued Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Payables And Accruals [Abstract]	'
Components of Accounts Payable and Other Accrued Liabilities	'
	The following table presents the components of accounts payable and other accrued liabilities (in thousands):
		December 31,
		2013		2012
	Accounts payable	$	168	$	331
	Other accrued liabilities		7,282		3,847
	Warranty settlement payments		2,187		—
	Payroll liabilities		2,162		—
	Property tax payable		3,490		3,444
	Sales tax payable		261		128
	Accounts payable and other accrued liabilities	$	15,550	$	7,750

Long_term_debt_Tables

Long term debt (Tables)	12 Months Ended
	Dec. 31, 2013
Debt Disclosure [Abstract]	'
Schedule of Long Term Debt	'
	The Company’s long term debt as of December 31, 2013 and 2012 is presented below (in thousands):
		December 31,						Interest Rate as of						Interest
								December 31,						Type
		2013			2012			2013			2012				Maturity
	Santa Isabel bridge loan	$	—		$	38,337			N/A			2.31	%	Variable	N/A
	Ocotillo bridge loan		—			56,586			N/A			3.31	%	Variable	N/A
	Hatchet Ridge term loan		239,865			251,119			1.43	%		1.43	%	Imputed	December 2032
	Gulf Wind term loan		166,448			174,969			3.25	%		3.36	%	Variable	Mar-20
	St. Joseph term loan		215,330			238,737			5.88	%		5.88	%	Fixed	May-31
	Spring Valley term loan		173,110			178,900			2.63	%		2.62	%	Variable	Jun-30
	Santa Isabel term loan		115,721			119,035			4.57	%		4.57	%	Fixed	September 2033
	Ocotillo commercial term loan		230,944			160,299			3	%		3.31	%	Variable	Aug-20
	Ocotillo development term loan		107,800			72,588			2.35	%		2.41	%	Variable	Aug-33
			1,249,218			1,290,570
	Less: current portion		(48,851	)		(137,258	)
		$	1,200,367		$	1,153,312
Summary of Amounts Due for Long Term Debt	'
	The following are amounts due for long-term debt as of December 31, 2013 (in thousands):
	For the year ending December 31,
	2014	$	48,851
	2015		58,888
	2016		60,442
	2017		61,571
	2018		66,547
	Thereafter		952,919
		$	1,249,218
Schedule of Commitment Fees Incurred and Interest Expense Recorded	'
	Interest and commitment fees incurred, and interest expense recorded in the Company’s consolidated statements of operations are as follows (in thousands):
		Year ended December 31,
		2013			2012			2011
	Interest and commitment fees incurred	$	57,478		$	43,496		$	31,610
	Capitalized interest, commitment fees, and letter of credit fees		(4,210	)		(10,259	)		(4,220	)
	Letter of credit fees		3,530			720			537
	Amortization of financing costs		6,816			2,545			1,477
	Interest expense	$	63,614		$	36,502		$	29,404

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation Disclosure [Abstract]	'
Reconciliation of Beginning and Ending Aggregate Carrying Amounts of Asset Retirement Obligations	'
	The following table presents a reconciliation of the beginning and ending aggregate carrying amounts of asset retirement obligations as of December 31, 2013, 2012 and 2011 (in thousands):
		December 31,
		2013			2012		2011
	Beginning asset retirement obligations	$	19,056		$	10,342	$	9,365
	Additions during the year		767			7,971		467
	Foreign currency translation adjustment		(172	)		59		(43	)
	Accretion expense		1,183			684		553
	Ending asset retirement obligations	$	20,834		$	19,056	$	10,342

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Schedule of Derivative Instruments Classified as Assets and Liabilities	'
	Undesignated Derivative Instruments Classified as Assets (Liabilities):
				As of						Year ended
				Fair Market Value						YTD Gain (Loss)
	Derivative Type	Quantity	Maturity	Current			Long-Term			Recognized into
			Dates	Portion			Portion			Income
	December 31, 2013
	Interest rate swaps	6	6/30/30	$	(3,899	)	$	14,358		$	15,367
	Interest rate cap	1	12/31/24		—			681			234
	Energy derivative	1	4/30/19		13,937			54,416			(11,272	)
				$	10,038		$	69,455		$	4,329
	December 31, 2012
	Interest rate swaps	6	6/30/30	$	(1,980	)	$	(2,931	)	$	(4,909	)
	Interest rate cap	1	12/31/24		—			447			(44	)
	Energy derivative	1	4/30/19		17,177			62,448			(6,951	)
				$	15,197		$	59,964		$	(11,904	)
	December 31, 2011
	Interest rate cap	1	12/31/24	$	—		$	491		$	(345	)
	Energy derivative	1	4/30/19		18,687			67,890			17,577
				$	18,687		$	68,381		$	17,232
	Designated Derivative Instruments Classified as Assets ( Liabilities):
				As of						Year ended
				Fair Market Value						YTD Gain (Loss)
	Derivative Type	Quantity	Maturity	Current			Long-Term			Recognized in
			Dates	Portion			Portion			OCI
	December 31, 2013
	Interest rate swaps	6	6/30/33	$	(2,105	)	$	9,625		$	10,434
	Interest rate swaps	7	3/15/20		(5,289	)		(7,439	)		9,398
	Interest rate swaps	2	6/28/30		(4,878	)		3,087			17,043
				$	(12,272	)	$	5,273		$	36,875
	December 31, 2012
	Interest rate swaps	6	6/30/33	$	(952	)	$	(1,962	)	$	(2,914	)
	Interest rate swaps	7	3/15/20		(5,558	)		(16,568	)		(1,835	)
	Interest rate swaps	2	6/28/30		(4,972	)		(13,865	)		(6,421	)
				$	(11,482	)	$	(32,395	)	$	(11,170	)
	December 31, 2011
	Interest rate swaps	7	3/15/20	$	(4,929	)	$	(15,362	)	$	(11,251	)
	Interest rate swaps	2	6/28/30		—			(12,416	)		(12,416	)
				$	(4,929	)	$	(27,778	)	$	(23,667	)

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2013
Equity [Abstract]	'
Schedule of Accumulated Other Comprehensive Income (Loss)	'
	The following table summarizes changes in the accumulated other comprehensive income (loss) balance by component:
		Foreign			Effective Portion of			Proportionate			Total
		Currency			Change in Fair Value			Share of Equity
					of Derivatives			Investee’s OCI
	Balances at January 1, 2011	$	(497	)	$	(9,040	)	$	—		$	(9,537	)
	Current period other comprehensive loss		(2,406	)		(23,667	)		—			(26,073	)
	Income tax benefit (expense)		—			—			—			—
	Balances at December 31, 2011		(2,903	)		(32,707	)		—			(35,610	)
	Current period other comprehensive income (loss)		2,749			(11,170	)		(1,475	)		(9,896	)
	Income tax benefit (expense)		—			—			—			—
	Balances at December 31, 2012		(154	)		(43,877	)		(1,475	)		(45,506	)
	Current period other comprehensive income (loss)		(8,309	)		36,875			2,621			31,187
	Income tax expense		—			—			(148	)		(148	)
	Grand acquisition		—			—			(4,217	)		(4,217	)
	Income tax benefit—Grand acquisition		—			—			1,307			1,307
	Balances at December 31, 2013	$	(8,463	)	$	(7,002	)	$	(1,912	)	$	(17,377	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Disclosures [Abstract]	'
Financial Assets and (Liabilities) Measured on Recurring Basis	'
	Financial assets and (liabilities) measured on a recurring basis:
		Fair Value Measurements Using
		Level 1			Level 2			Level 3
	December 31, 2013
	Interest rate swaps	$	—		$	3,460		$	—
	Interest rate cap		—			681			—
	Energy derivative		—			—			68,353
		$	—		$	4,141		$	68,353
	December 31, 2012
	Interest rate swaps	$	—		$	(48,788	)	$	—
	Interest rate cap		—			447			—
	Energy derivative		—			—			79,625
	Contingent liabilities		—			—			(8,001	)
		$	—		$	(48,341	)	$	71,624
Reconciliation of Energy Derivative and Contingent Liabilities Measured at Fair Value	'
	Reconciliation of energy derivative and contingent liabilities measured at fair value using unobservable inputs (Level 3):
		Contingent			Energy			Total
		Liabilities			Derivative
	Balances at January 1, 2012	$	(5,986	)	$	86,577		$	80,591
	Settlements		—			(19,644	)		(19,644	)
	Change in fair value, net of settlements		(2,015	)		12,692			10,677
	Balances at December 31, 2012		(8,001	)		79,625			71,624
	Settlements		8,001			(16,798	)		(8,797	)
	Change in fair value, net of settlements		—			5,526			5,526
	Balances at December 31, 2013	$	—		$	68,353		$	68,353
Carrying Amounts and Fair Values of Company's Long Term Debt	'
	The following table presents the carrying amounts and fair values of the Company’s long term debt (in thousands):
		December 31, 2013						December 31, 2012
		Carrying			Fair Value			Carrying			Fair Value
		Amount						Amount
	Total long term debt	$	1,249,218		$	1,165,119		$	1,290,570		$	1,247,449

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
Components of Provision for Income Taxes	'
	The following table presents significant components of the provision for income taxes (in thousands):
		Year ended December 31,
		2013			2012			2011
	Current
	U.S. federal	$	—		$	—		$	—
	State		—			—			—
	Foreign		—			—			—
			—			—			—
	Deferred
	U.S. federal		2,961			—			—
	State		—			—			—
	Foreign		1,585			(3,604	)		689
			4,546			(3,604	)		689
	Total income tax (benefit) provision	$	4,546		$	(3,604	)	$	689
Domestic and Foreign Components of Net Income (Loss) Before Income Tax (Benefit) Expense	'
	The following table presents the domestic and foreign components of net income (loss) before income tax (benefit) expense (in thousands):
		Year ended December 31,
		2013			2012			2011
	U.S.	$	4,022		$	(17,810	)	$	25,957
	Foreign		10,596			830			638
	Total	$	14,618		$	(16,980	)	$	26,595
Reconciliation of Statutory U.S Federal Income Tax Rate to Effective Tax Rate	'
	The following table presents a reconciliation of the statutory U.S federal income tax rate to the Company’s effective tax rate, as a percentage of income before taxes for the years ended December 31, 2013, 2012 and 2011:
		Year ended December 31,
		2013			2012			2011
	Statutory U.S. federal tax rate		35	%		35	%		35	%
	Book/tax basis difference		—			27.2	%		—
	Partnership income not subject to taxes		—			(40.9	)%		(32.4	)%
	Adjustment for income in non-taxable entities allocable to noncontrolling interest		16.5	%		—			—
	Foreign rate difference
	Tax rate differential on pre-tax book income, other		2.1	%		—			—
	Local tax on branch profits/(losses)—Puerto Rico		13.1	%		—			—
	Permanent book/tax differences (domestic only)		(2.2	)%		—			—
	Valuation allowance		187.2	%		—			—
	Other		3.1	%		—			—
	ARRA Section 1603 grant-basis reduction deferred tax assets		(223.7	)%		—			—
	Effective income tax rate		31.1	%		21.3	%		2.6	%
Components of Deferred Tax Assets and Deferred Tax Liabilities	'
	The following table presents significant components of the Company’s deferred tax assets and deferred tax liabilities as of December 31, 2013 and 2012 (in thousands):
		December 31,
		2013			2012
	Deferred tax assets/liabilities—current
	Other current deferred tax assets and liabilities	$	2,399		$	—
	Basis difference in derivatives		2,835			—
	Total gross deferred tax assets/(liabilities)		5,234			—
	Less: valuation allowance		(4,661	)		—
	Total net deferred tax assets/(liabilities)—current		573			—
	Deferred tax assets/(liabilities)—non-current:
	Property, plant and equipment		(36,548	)		(47,894	)
	Basis difference in foreign subsidiaries		40,097			—
	Partnership interest		(4,917	)		—
	Lease Hatchet Ridge		29,314			—
	Asset retirement obligation		4,649			—
	Equity method		3,794			—
	Unrealized loss on derivatives		(5,830	)		—
	Net operating loss carryforwards		61,441			45,302
	Other non current deferred tax assets and liabilities		(4,595	)		(690	)
	Change in tax status		—			4,599
	Accruals not currently deductible		—			443
	Total gross deferred tax assets/(liabilities)—non-current		87,405			1,760
	Less: valuation allowance		(95,318	)		(482	)
	Total net deferred tax assets/(liabilities)—non-current		(7,913	)		1,278
	Total net deferred tax assets/(liabilities)	$	(7,340	)	$	1,278

Equity_Incentive_Award_Plan_Ta

Equity Incentive Award Plan (Tables)	12 Months Ended
	Dec. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Summary of Restricted Stock Awards Activity	'
	The following table summarizes restricted stock awards activity under the 2013 Plan for the year ended December 31, 2013:
		Number of RSAs			Weighted Average		Aggregate
		Outstanding			Grant Date		Intrinsic
					Fair Value		Value
	Balance at October 2, 2013		—		$	—
	Granted		86,620			22.71
	Released		(9,424	)		24.15
	Repurchased for employee tax withholding		(934	)		22.53
	Balance at December 31, 2013		76,262		$	22.53	$	2,311,501
Summary Stock Option Activity	'
	The following table summarizes stock option activity under the 2013 Plan for the year ended December 31, 2013:
		Number of			Weighted Average		Weighted Average		Aggregate
		Options			Exercise Price		Remaining		Instrinsic Value
		Outstanding					Contractual Life
							(in years)
	Balance at October 2, 2013		—		$	—
	Granted		444,823			22.00
	Vested		(37,069	)		22
	Exercised		—			—
	Expired		—			—
	Forfeited		—			—
	Balance at December 31, 2013		407,754		$	22		9.8	$	3,388,436
	Exercisable at December 31, 2013		37,069		$	22		9.8	$	308,043
Schedule of Weighted Average Assumptions	'
	The following weighted average assumptions were used:
		Year ended
		December 31, 2013
	Stock options:
	Risk-free interest rate		1.68	%
	Expected life (in years)		5.8
	Expected volatility		36	%
	Expected dividend yield		5.7

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2013
Earnings Per Share [Abstract]	'
Schedule of Consolidated Statements of Operations Before and After IPO	'
	The following table provides a disaggregated presentation of the Company’s consolidated statements of operations before and after its IPO on October 2, 2103:
	Pattern Energy Group Inc.
	Consolidated Statements of Operations
	(In thousands of U.S. dollars, except share data)
		From October 2, 2013			From January 1, 2013			For Year Ended
		to December 31, 2013			to October 1, 2013			December 31, 2013
	Revenue:
	Electricity sales	$	41,836		$	131,434		$	173,270
	Energy derivative settlements		4,035			12,763			16,798
	Unrealized loss on energy derivative		(4,916	)		(6,356	)		(11,272	)
	Related party revenue		446			465			911
	Other revenue		701			21,165			21,866
	Total revenue		42,102			159,471			201,573
	Cost of revenue:
	Project expense		15,455			42,222			57,677
	Depreciation and accretion		21,193			61,987			83,180
	Total cost of revenue		36,648			104,209			140,857
	Gross profit		5,454			55,262			60,716
	Total operating expenses		3,456			9,532			12,988
	Operating income		1,998			45,730			47,728
	Other expense		(10,217	)		(22,893	)		(33,110	)
	Net (loss) income before income tax		(8,219	)		22,837			14,618
	Tax provision (benefit)		11,314			(6,768	)		4,546
	Net (loss) income		(19,533	)		29,605			10,072
	Net loss attributable to noncontrolling interest		(6,197	)		(690	)		(6,887	)
	Net (loss) income attributable to controlling interest	$	(13,336	)	$	30,295		$	16,959
	Earnings per share information:
	Less: Net income attributable to controlling interest prior to the IPO on October 2, 2013								(30,295	)
	Net loss attributable to controlling interest subsequent to the IPO							$	(13,336	)
	Numerator for basic and diluted earnings (loss) per share:
	Net earnings (loss)							$	(13,336	)
	Less: dividends declared
	Class A common stock								(11,103	)
	Class B common stock								—
								$	(24,439	)
	Undistributed earnings (loss)
	Denominator for basic and diluted earnings (loss) per share:
	Weighted average number of shares:
	Class A common stock								35,448,056
	Class B common stock								15,555,000
	Total								51,003,056
	Calculation of basic and diluted earnings (loss) per share:
	Class A common stock:
	Dividends							$	0.31
	Undistributed loss								(0.48	)
	Basic and diluted loss per share							$	(0.17	)
	Class B common stock:
	Dividends							$	—
	Undistributed loss								(0.48	)
	Basic and diluted loss per share							$	(0.48	)

Geographic_Information_Tables

Geographic Information (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
Summary of Geographical Revenues and Assets	'
	The table below provides information, by country, about the Company’s consolidated operations. Revenue is recorded in the country in which it is earned and assets are recorded in the country in which they are located (in thousands):
		Revenue						Property, Plant and Equipment, net
		Year ended December 31,						December 31,
		2013		2012		2011		2013		2012
	United States	$	161,505	$	73,089	$	103,773	$	1,210,319	$	1,367,149
	Canada		40,068		41,439		32,086		265,823		301,153
	Total	$	201,573	$	114,528	$	135,859	$	1,476,142	$	1,668,302

Commitments_Contingencies_and_1

Commitments, Contingencies and Warranties (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Schedule of Turbine Operations and Maintenance Commitments	'
	The following table presents turbine operations and maintenance commitments over the next five years (in thousands):
	For the year ending December 31,
	2014	$	16,465
	2015		3,845
	2016		2,188
	2017		1,965
	2018		55
	Thereafter		591
	Total	$	25,109
Schedule of Future Minimum Payments Related to Land Leases	'
	The future minimum payments related to these leases as of December 31, 2013, are as follows (in thousands):
	For the year ending December 31,
	2014	$	3,713
	2015		3,717
	2016		3,725
	2017		3,731
	2018		3,738
	Thereafter		91,876
	Total	$	110,500

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2013
Related Party Transactions [Abstract]	'
Allocated Costs Included in Combined Statement of Operations	'
	The table below presents allocated costs prior to October 2, 2013 and net bilateral management service cost reimbursements on and after October 2, 2013 included in the consolidated statements of operations (in thousands):
		December 31,
		2013			2012			2011
	Project expense	$	1,995		$	1,998		$	1,139
	General and administrative		7,318			10,604			8,098
	Management Services Agreement expense		851			—			—
	Management Services Agreement income		(665	)		—			—
	Other income		(551	)		(210	)		(199	)
	Total	$	8,948		$	12,392		$	9,038

Selected_Quarterly_Financial_D1

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]	'
Summary of Quarterly Consolidated Statements of Operations	'
	The following tables summarize the Company’s unaudited quarterly consolidated statements of operations for each of the eight quarters in the period ended December 31, 2013. The quarterly consolidated statements of operations data were prepared on a basis consistent with the audited consolidated financial statements included in Part III, Item 14, “Financial Statements and Supplementary Data” in this Annual Report on Form 10-K.
	Quarterly financial data in thousands, except for share data:
		Three months ended
		December 31,			September 30,			June 30,			March 31,
		2013			2013			2013			2013
	Revenue	$	41,767		$	57,257		$	58,712		$	43,837
	Gross profit		4,729			21,471			26,222			8,294
	Net (loss) income		(19,376	)		4,244			43,988			(18,784	)
	Net (loss) income attributable to noncontrolling interest		(6,197	)		3,248			(359	)		(3,579	)
	Net (loss) income attributable to controlling interest		(13,179	)		996			44,347			(15,205	)
	Basic and diluted loss per share—Class A	$	(0.17	)		N/A			N/A			N/A
	Basic and diluted loss per share—Class B	$	(0.48	)		N/A			N/A			N/A
		Three months ended
		December 31,			September 30,			June 30,			March 31,
		2012			2012			2012			2012
	Revenue	$	34,345		$	16,903		$	24,939		$	38,341
	Gross profit (loss)		10,086			(5,213	)		6,175			19,610
	Net (loss) income		(4,455	)		(16,913	)		(575	)		8,567
	Net (loss) income attributable to noncontrolling interest		(1,147	)		(7,494	)		(2,928	)		4,480
	Net (loss) income attributable to controlling interest		(3,308	)		(9,419	)		2,353			4,087
	Basic and diluted loss per share—Class A		N/A			N/A			N/A			N/A
	Basic and diluted loss per share—Class B		N/A			N/A			N/A			N/A

Organization_Additional_Inform

Organization - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

1 Months Ended

1 Months Ended

1 Months Ended

12 Months Ended

Dec. 31, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Oct. 02, 2013

Dec. 31, 2013

Oct. 02, 2013

Dec. 31, 2013

Oct. 02, 2013

Oct. 02, 2013

Oct. 02, 2013

Oct. 02, 2013

Oct. 02, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Oct. 17, 2012

Sep. 24, 2013

Sep. 24, 2013

Sep. 24, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Class A common stock [Member]

Class A common stock [Member]

Class A common stock [Member]

Class B common stock [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Energy [Member]

Corporate Joint Venture [Member]

Pattern Renewables LP [Member]

Pattern Energy Group Inc. [Member]

Pattern Energy Group Inc. [Member]

Pattern Energy Group Inc. [Member]

Pattern Energy Unconsolidated [Member]

Pattern Energy Unconsolidated [Member]

Hatchet Ridge [Member]

St Josephs [Member]

Spring Valley [Member]

Pattern santa Isabel LLC [Member]

Ocotillo [Member]

IPO [Member]

Project

Projects in operation [Member]

Projects under construction [Member]

Class A common stock [Member]

Class A common stock [Member]

Class B common stock [Member]

Cash Distribution [Member]

Cash Distribution [Member]

Cash Distribution [Member]

Class A common stock [Member]

Class B common stock [Member]

Maximum [Member]

Maximum [Member]

Project

Project

IPO [Member]

Schedule Of Description Of Business [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Issuance of common stock

'

'

'

'

'

35,530,786

100

'

15,555,000

'

'

'

'

19,445,000

'

15,555,000

'

'

'

100

'

'

'

'

'

'

'

'

'

'

Ownership interest

'

'

'

'

'

'

'

'

'

'

40.00%

'

'

'

'

'

27.00%

40.00%

33.00%

100.00%

'

'

'

'

'

100.00%

100.00%

100.00%

100.00%

100.00%

Common stock, shares authorized

'

'

'

'

'

500,000,000

500,000,000

'

20,000,000

'

'

'

'

'

'

'

'

'

'

'

620,000,000

500,000,000

20,000,000

'

'

'

'

'

'

'

Preferred stock, shares authorized

100,000,000

'

100,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100,000,000

'

'

'

'

'

'

'

'

'

Shares issued in initial public offering

'

'

'

'

'

'

'

16,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Net proceeds from issuance of shares

'

'

$317,926,000

'

'

'

'

$317,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Portion of net proceeds utilized as consideration

'

'

30,070,000

'

'

'

'

'

'

232,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of shares purchased upon exercise of overallotment option

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of wind power projects

'

'

'

'

'

'

'

'

'

8

'

6

2

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Prior period expense of entity

$3,456,000

$9,532,000

$12,988,000

$11,636,000

$9,668,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$10,000

$10,000

'

'

'

'

'

Summary_of_Significant_Account3

Summary of Significant Accounting Policies - Schedule of Percentages of Total Revenues from Significant Customers (Detail) (Total Revenue [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Manitoba Hydro [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Concentrations of credit risk	17.62%	32.06%	20.91%
San Diego Gas And Electric [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Concentrations of credit risk	17.23%	0.18%	0.00%
Pacific Gas and Electric [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Concentrations of credit risk	14.54%	23.12%	20.67%
Electric Reliability Council Of Texas [Member]	'	'	'
Concentration Risk [Line Items]	'	'	'
Concentrations of credit risk	12.24%	18.28%	35.23%

Summary_of_Significant_Account4

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013
Significant Accounting Policies [Line Items]	'
Asset impairment charges	$0
Maximum tax benefit likely to be realized upon ultimate settlement, percentage	50.00%
Minimum [Member]	'
Significant Accounting Policies [Line Items]	'
Property, plant and equipment useful lives	'3 years
Maximum [Member]	'
Significant Accounting Policies [Line Items]	'
Property, plant and equipment useful lives	'5 years
Gulf Wind [Member]	'
Significant Accounting Policies [Line Items]	'
Fixed price of derivative instrument	58.00%
Credit Suisse [Member] | Gulf Wind [Member]	'
Significant Accounting Policies [Line Items]	'
Description of derivative swap	'The counterparty to a 10-year fixed-for-floating swap related to annual electricity generation at the Company's Gulf Wind project.
Term of energy derivative instrument acquired	'10 years
Wind Farm [Member]	'
Significant Accounting Policies [Line Items]	'
Property, plant and equipment useful lives	'20 years

Acquisition_from_Pattern_Devel1

Acquisition from Pattern Development - Additional Information (Detail) (Grand [Member], USD $)	0 Months Ended	12 Months Ended
	Dec. 20, 2013	Dec. 31, 2013
Grand [Member]	'	'
Loans At Acquisition Date [Line Items]	'	'
Business acquisition, percentage of equity interest	45.00%	'
Business acquisition price	$79,500,000	'
Business acquisition, contingent payment	$4,700,000	'
Power Purchase Agreement period	'20 years	'
Effective date of acquisition	'	20-Dec-13

Prepaid_Expenses_and_Other_Cur2

Prepaid Expenses and Other Current Assets - Components of Prepaid Expenses and Other Current Assets (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]	'	'
Prepaid expenses	$10,132	$7,202
Sales tax	50	3,275
Interconnection network upgrade receivable	2,512	1,854
Other current assets	1,233	1,463
Prepaid expenses and other current assets	$13,927	$13,794

Property_Plant_and_Equipment_S

Property, Plant and Equipment - Schedule of Property, Plant and Equipment (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment [Line Items]	'	'
Subtotal	$1,655,920,000	$1,768,549,000
Less: Accumulated depreciation	-179,778,000	-100,247,000
Property, plant and equipment, net	1,476,142,000	1,668,302,000
Operating wind farms [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Subtotal	1,652,119,000	1,765,200,000
Furniture, fixtures and equipment [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Subtotal	3,785,000	3,333,000
Land [Member]	'	'
Property, Plant and Equipment [Line Items]	'	'
Subtotal	$16,000	$16,000

Property_Plant_and_Equipment_A

Property, Plant and Equipment - Additional Information (Detail) (USD $)	12 Months Ended			6 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
				Ocotillo [Member]	Pattern santa Isabel LLC [Member]	Spring Valley [Member]
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'
Depreciation expense related to property, plant and equipment	$82,000,000	$48,300,000	$38,900,000	'	'	'
Cash grant received	'	'	'	115,900,000	57,600,000	79,900,000
Decrease in depreciation expense	$13,000,000	$1,500,000	'	'	'	'

Unconsolidated_Investments_Sch

Unconsolidated Investments - Schedule of Projects Accounted under Equity Method of Accounting (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Schedule of Equity Method Investments [Line Items]	'	'
Unconsolidated investments	$107,055	$36,218
Pattern Energy Predecessor [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Unconsolidated investments	107,055	36,218
Pattern Energy Predecessor [Member] | South Kent [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Unconsolidated investments	59,488	17,895
Percentage of ownership	50.00%	50.00%
Pattern Energy Predecessor [Member] | El Arrayan [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Unconsolidated investments	21,103	18,323
Percentage of ownership	31.50%	31.50%
Pattern Energy Predecessor [Member] | Grand [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
Unconsolidated investments	$26,464	'
Percentage of ownership	45.00%	'

Unconsolidated_Investments_Add

Unconsolidated Investments - Additional Information (Detail) (USD $)	0 Months Ended	12 Months Ended
	Dec. 20, 2013	Dec. 31, 2013
South Kent [Member] | Pattern Energy Predecessor [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
PPA of project	'	'20 years
El Arrayan [Member] | Pattern Energy Predecessor [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
PPA of project	'	'P20Y
Grand [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
PPA of project	'20 years	'
Business acquisition, percentage of equity interest	45.00%	'
Business acquisition price	$79,500,000	'
Business acquisition, contingent payment	4,700,000	'
Grand [Member] | Pattern Energy Predecessor [Member]	'	'
Schedule of Equity Method Investments [Line Items]	'	'
PPA of project	'	'P20Y
Business acquisition, percentage of equity interest	45.00%	'
Business acquisition price	79,500,000	'
Business acquisition, contingent payment	$4,700,000	'

Unconsolidated_Investments_Sum

Unconsolidated Investments - Summary of Aggregated Balance Sheets and Operating Results of Unconsolidated Joint Ventures (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Equity Method Investments And Joint Ventures [Abstract]	'	'	'
Current assets	$78,906	$33,578	'
Non-current assets	1,097,018	142,522	'
Total assets	1,175,924	176,100	'
Current liabilities	128,076	5,153	'
Non-current liabilities	810,936	71,709	'
Total liabilities	939,012	76,862	'
Total equity	236,912	99,238	'
Total liabilities and equity	1,175,924	176,100	'
Revenue	'	'	'
Other (income) expense	7,846	-40	-205
Net income (loss)	$13,322	($275)	($455)

Accounts_Payable_and_Other_Acc2

Accounts Payable and Other Accrued Liabilities - Components of Accounts Payable and Other Accrued Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Payables And Accruals [Abstract]	'	'
Accounts payable	$168	$331
Other accrued liabilities	7,282	3,847
Warranty settlement payments	2,187	'
Payroll liabilities	2,162	'
Property tax payable	3,490	3,444
Sales tax payable	261	128
Accounts payable and other accrued liabilities	$15,550	$7,750

Long_Term_Debt_Schedule_of_Lon

Long Term Debt - Schedule of Long Term Debt (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Oct. 31, 2012
Debt Instrument [Line Items]	'	'	'
Long term debt	$1,249,218,000	$1,290,570,000	'
Less: Current Portion	-48,851,000	-137,258,000	'
Long term debt, noncurrent	1,200,367,000	1,153,312,000	'
Santa Isabel bridge loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	'	38,337,000	'
Long term debt, Interest Rate	'	2.31%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'N/A	'	'
Ocotillo bridge loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	'	56,586,000	467,300,000
Long term debt, Interest Rate	'	3.31%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'N/A	'	'
Hatchet Ridge term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	239,865,000	251,119,000	'
Long term debt, Interest Rate	1.43%	1.43%	'
Long term debt, Interest Type	'Imputed	'	'
Long term debt, Maturity	'December 2032	'	'
Gulf Wind credit facility [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	166,448,000	174,969,000	'
Long term debt, Interest Rate	3.25%	3.36%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'March 2020	'	'
St. Joseph term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	215,330,000	238,737,000	'
Long term debt, Interest Rate	5.88%	5.88%	'
Long term debt, Interest Type	'Fixed	'	'
Long term debt, Maturity	'May 2031	'	'
Spring Valley term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	173,110,000	178,900,000	'
Long term debt, Interest Rate	2.63%	2.62%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'June 2030	'	'
Santa Isabel term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	115,721,000	119,035,000	'
Long term debt, Interest Rate	4.57%	4.57%	'
Long term debt, Interest Type	'Fixed	'	'
Long term debt, Maturity	'September 2033	'	'
Ocotillo commercial term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	230,944,000	160,299,000	'
Long term debt, Interest Rate	3.00%	3.31%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'August 2020	'	'
Ocotillo development term loan [Member]	'	'	'
Debt Instrument [Line Items]	'	'	'
Long term debt	$107,800,000	$72,588,000	'
Long term debt, Interest Rate	2.35%	2.41%	'
Long term debt, Interest Type	'Variable	'	'
Long term debt, Maturity	'August 2033	'	'

Long_Term_Debt_Summary_of_Amou

Long Term Debt - Summary of Amounts Due for Long Term Debt (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013
	USD ($)	USD ($)	South Kent Wind LP [Member]
			CAD
Debt Instrument [Line Items]	'	'	'
2014	$48,851,000	'	1,914,367
2015	58,888,000	'	23,185,104
2016	60,442,000	'	22,109,351
2017	61,571,000	'	25,773,416
2018	66,547,000	'	26,819,083
Thereafter	952,919,000	'	444,830,873
Long-term debt	$1,249,218,000	$1,290,570,000	544,632,194

Long_Term_Debt_Schedule_of_Com

Long Term Debt - Schedule of Commitment Fees Incurred and Interest Expense Recorded (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Debt Disclosure [Abstract]	'	'	'
Interest and commitment fees incurred	$57,478	$43,496	$31,610
Capitalized interest, commitment fees, and letter of credit fees	-4,210	-10,259	-4,220
Letter of credit fees	3,530	720	537
Amortization of financing costs	6,816	2,546	1,477
Interest expense	$63,614	$36,502	$29,404

Long_Term_Debt_Additional_Info

Long Term Debt - Additional Information (Detail) (USD $)

12 Months Ended

1 Months Ended

0 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Sep. 30, 2013

Sep. 30, 2013

Nov. 15, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2012

Dec. 31, 2013

Oct. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Development bank loan [Member]

Commercial bank loan [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Revolving Credit Facility [Member]

Hatchet Ridge term loan [Member]

Hatchet Ridge term loan [Member]

Gulf Wind credit facility [Member]

Gulf Wind credit facility [Member]

St. Joseph term loan [Member]

St. Joseph term loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Ocotillo bridge loan [Member]

Santa Isabel term loan [Member]

Santa Isabel term loan [Member]

Santa Isabel term loan [Member]

Spring Valley term loan [Member]

Spring Valley term loan [Member]

SecurityLoan

Interest rate swaps [Member]

Letter of credit [Member]

Development bank loan [Member]

Development bank loan [Member]

Commercial bank loan [Member]

Commercial bank loan [Member]

Tranche Loan [Member]

Tranche Loan [Member]

Tranche Loan [Member]

Tranche Loan [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Credit facility maturity period

'

'

'

'

'4 years

'

'

'22 years

'

'10 years

'

'20 years

'

'

'

'

'

'

'20 years

'

'7 years

'

'

'

'

'

'

Credit facility amount outstanding

'

'

'

'

'

'

'

'

'

$195,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Construction loan facility

'

'

'

'

'

'

'

'

'

'

'

259,500,000

'

'

'

351,500,000

'

'

'

110,000,000

'

241,500,000

'

119,000,000

'

178,900,000

'

Cash grant for bridge loan

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

57,500,000

'

53,300,000

'

Debt maturity period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Sep-33

'

'

'

'

Loan facility

1,249,218,000

1,290,570,000

'

'

'

'

'

239,865,000

251,119,000

166,448,000

174,969,000

215,330,000

238,737,000

'

56,586,000

467,300,000

'

'

'

'

'

'

115,721,000

'

119,035,000

173,110,000

178,900,000

Number of construction loan

'

'

'

'

'

'

'

'

'

'

'

'

'

2

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit facility

'

'

'

'

120,000,000

'

'

'

'

'

'

'

'

56,600,000

'

'

'

59,200,000

'

'

'

'

'

'

'

'

'

Percentage of loan commitment in interest rate swaps

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

90.00%

'

'

'

'

'

'

'

'

'

'

Prepaid bank loan

'

'

2,200,000

5,300,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Increase of available borrowings

'

'

'

'

'

35,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Letters of credit issued

'

'

'

'

'

44,800,000

39,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revolving credit facility outstanding amount

$0

$0

'

'

'

$56,000,000

$0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Description of base rate

'The base rate loans accrue interest at 2.5% plus the greatest of the (i) the prime rate, (ii) the federal funds rate plus 0.5% and (iii) the Eurodollar rate that would be in effect for a Eurodollar rate loan with an interest period of one month plus 1.0%. The Eurodollar rate loans will accrue interest at a rate per annum equal to LIBOR, as published by Reuters plus 3.5%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Asset_Retirement_Obligations_A

Asset Retirement Obligations - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation [Abstract]	'
Estimated asset retirement period	'20 years
Asset retirement obligations, description	'The Company's asset retirement obligations represent the estimated cost of decommissioning the turbines, removing above-ground installations and restoring the sites at a date that is 20 years from the commencement of commercial operation of the facility.

Asset_Retirement_Obligations_R

Asset Retirement Obligations - Reconciliation of Beginning and Ending Aggregate Carrying Amounts of Asset Retirement Obligations (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Asset Retirement Obligation Disclosure [Abstract]	'	'	'
Beginning asset retirement obligations	$19,056	$10,342	$9,365
Additions during the year	767	7,971	467
Foreign currency translation adjustment	-172	59	-43
Accretion expense	1,183	684	553
Ending asset retirement obligations	$20,834	$19,056	$10,342

Derivative_Instruments_Schedul

Derivative Instruments - Schedule of Derivative Instruments Classified as Assets and Liabilities (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivatives, Fair Value [Line Items]	'	'	'
Fair Market Value, Current Portion	$13,937,000	$17,177,000	'
Fair Market Value, Current Portion	-16,171,000	-13,462,000	'
Fair Market Value, Long-Term Portion	82,167,000	62,895,000	'
Fair Market Value, Long-Term Portion	-7,439,000	-35,326,000	'
Gain (loss) Recognized in OCI	36,875,000	-11,170,000	-23,667,000
Undesignated Derivative Instruments [Member] | Derivative Assets (Liabilities) [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Fair Market Value, Current Portion	10,038,000	15,197,000	18,687,000
Fair Market Value, Long-Term Portion	69,455,000	59,964,000	68,381,000
Gain (loss) Recognized into Income	4,329,000	-11,904,000	17,232,000
Undesignated Derivative Instruments [Member] | Interest rate swaps [Member] | Derivative Assets (Liabilities) [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	6	6	'
Maturity Dates	30-Jun-30	30-Jun-30	'
Fair Market Value, Current Portion	-3,899,000	-1,980,000	'
Fair Market Value, Long-Term Portion	14,358,000	-2,931,000	'
Gain (loss) Recognized into Income	15,367,000	-4,909,000	'
Undesignated Derivative Instruments [Member] | Interest rate cap [Member] | Derivative Assets (Liabilities) [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	1	1	1
Maturity Dates	31-Dec-24	31-Dec-24	31-Dec-24
Fair Market Value, Current Portion	'	'	'
Fair Market Value, Long-Term Portion	681,000	447,000	491,000
Gain (loss) Recognized into Income	234,000	-44,000	-345,000
Undesignated Derivative Instruments [Member] | Energy derivative [Member] | Derivative Assets (Liabilities) [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	1	1	1
Maturity Dates	30-Apr-19	30-Apr-19	30-Apr-19
Fair Market Value, Current Portion	13,937,000	17,177,000	18,687,000
Fair Market Value, Long-Term Portion	54,416,000	62,448,000	67,890,000
Gain (loss) Recognized into Income	-11,272,000	-6,951,000	17,577,000
Designated Derivative Instruments [Member] | Derivative Assets (Liabilities) [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Fair Market Value, Current Portion	-12,272,000	-11,482,000	-4,929,000
Fair Market Value, Long-Term Portion	5,273,000	-32,395,000	-27,778,000
Gain (loss) Recognized in OCI	36,875,000	-11,170,000	-23,667,000
Designated Derivative Instruments [Member] | Interest rate swaps [Member] | Derivative Assets (Liabilities) [Member] | Maturity Date, 6/30/2033 [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	6	6	'
Maturity Dates	30-Jun-33	30-Jun-33	'
Fair Market Value, Current Portion	-2,105,000	-952,000	'
Fair Market Value, Long-Term Portion	9,625,000	-1,962,000	'
Gain (loss) Recognized in OCI	10,434,000	-2,914,000	'
Designated Derivative Instruments [Member] | Interest rate swaps [Member] | Derivative Assets (Liabilities) [Member] | Maturity Date, 3/15/2020 [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	7	7	7
Maturity Dates	15-Mar-20	15-Mar-20	15-Mar-20
Fair Market Value, Current Portion	-5,289,000	-5,558,000	-4,929,000
Fair Market Value, Long-Term Portion	-7,439,000	-16,568,000	-15,362,000
Gain (loss) Recognized in OCI	9,398,000	-1,835,000	-11,251,000
Designated Derivative Instruments [Member] | Interest rate swaps [Member] | Derivative Assets (Liabilities) [Member] | Maturity Date, 6/28/2030 [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Quantity	2	2	2
Maturity Dates	28-Jun-30	28-Jun-30	28-Jun-30
Fair Market Value, Current Portion	-4,878,000	-4,972,000	'
Fair Market Value, Long-Term Portion	3,087,000	-13,865,000	-12,416,000
Gain (loss) Recognized in OCI	$17,043,000	($6,421,000)	($12,416,000)

Derivative_Instruments_Additio

Derivative Instruments - Additional Information (Detail) (USD $)

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Oct. 31, 2012

Oct. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Gulf Wind [Member]

Interest rate cap [Member]

Interest rate cap [Member]

Interest rate cap [Member]

Energy derivative [Member]

Energy derivative [Member]

Energy derivative [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Interest rate swaps [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Spring Valley [Member]

Spring Valley [Member]

Spring Valley [Member]

Ocotillo [Member]

Ocotillo [Member]

Ocotillo [Member]

Ocotillo [Member]

Two through eight years [Member]

Year nine [Member]

Year ten [Member]

Development bank term loans [Member]

Commercial bank term loans [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Gulf Wind [Member]

Derivatives, Fair Value [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Variable interest rate exchange for fixed interest rate payments

'

'

'

'

'

'

'

'

'

'

6.60%

6.60%

6.60%

'

'

5.50%

'

'

2.50%

2.20%

'

'

'

Fixed interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6.60%

7.10%

7.60%

Recorded cash flow hedge ineffectiveness

'

'

'

'

'

'

'

'

'

'

$0

$0

$0

$0

$0

$0

$0

$0

'

'

'

'

'

Reclassification into earnings from accumulated other comprehensive income (loss)

'

'

'

'

'

'

'

'

'

'

5,300,000

'

'

4,900,000

'

'

2,100,000

'

'

'

'

'

'

Derivative future rate

'

'

'

'

6.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative effective date

'

'

'

'

31-Mar-20

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Term of loan to be refinanced

'

'

'

'

'10 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative maturity date

'

'

'

'

31-Dec-24

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notional amount reduced quarterly

'

'

'

'

42,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrealized gains (losses)

15,601,000

-4,953,000

-345,000

'

200,000

0

300,000

-11,300,000

-7,000,000

17,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative instrument asset value

'

'

'

'

700,000

400,000

500,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Fixed price of derivative instrument

'

'

'

58.00%

'

'

'

58.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Derivative instrument, fair value

'

'

'

'

'

'

'

$68,400,000

$79,600,000

$86,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt interest rate increases by every four years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

0.25%

'

'

'

'

'

'

'

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Loss) - Schedule of Accumulated Other Comprehensive Income (Loss) (Detail) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Beginning Balance	'	($34,264)	($34,264)	($35,610)	($9,537)
Current period other comprehensive income (loss)	6,847	24,192	31,039	-9,896	-26,073
Income tax benefit (expense)	'	'	-148	'	'
Accumulated Other Comprehensive Income (Loss), Ending Balance	-8,353	'	-8,353	-34,264	-35,610
Grand [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Acquisition	'	'	-4,217	'	'
Income tax benefit - acquisition	'	'	1,307	'	'
Foreign Currency [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Beginning Balance	'	-154	-154	-2,903	-497
Current period other comprehensive income (loss)	'	'	-8,309	2,749	-2,406
Income tax benefit (expense)	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Ending Balance	-8,463	'	-8,463	-154	-2,903
Foreign Currency [Member] | Grand [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Acquisition	'	'	'	'	'
Income tax benefit - acquisition	'	'	'	'	'
Effective Portion of Change in Fair Value of Derivatives [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Beginning Balance	'	-43,877	-43,877	-32,707	-9,040
Current period other comprehensive income (loss)	'	'	36,875	-11,170	-23,667
Income tax benefit (expense)	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Ending Balance	-7,002	'	-7,002	-43,877	-32,707
Effective Portion of Change in Fair Value of Derivatives [Member] | Grand [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Acquisition	'	'	'	'	'
Income tax benefit - acquisition	'	'	'	'	'
Proportionate Share of Equity Investee's OCI [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss), Beginning Balance	'	-1,475	-1,475	'	'
Current period other comprehensive income (loss)	'	'	2,621	-1,475	'
Income tax benefit (expense)	'	'	-148	'	'
Accumulated Other Comprehensive Income (Loss), Ending Balance	-1,912	'	-1,912	-1,475	'
Proportionate Share of Equity Investee's OCI [Member] | Grand [Member]	'	'	'	'	'
Accumulated Other Comprehensive Income (Loss) [Line Items]	'	'	'	'	'
Acquisition	'	'	-4,217	'	'
Income tax benefit - acquisition	'	'	$1,307	'	'

Fair_Value_Measurements_Financ

Fair Value Measurements - Financial Assets and (Liabilities) Measured on Recurring Basis (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Level 1 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 1 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 1 [Member] | Interest rate cap [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 1 [Member] | Energy derivative [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 1 [Member] | Contingent Liabilities [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 2 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	4,141,000	-48,341,000
Level 2 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	3,460,000	-48,788,000
Level 2 [Member] | Interest rate cap [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	681,000	447,000
Level 2 [Member] | Energy derivative [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 2 [Member] | Contingent Liabilities [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 3 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	68,353,000	71,624,000
Level 3 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 3 [Member] | Interest rate cap [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 3 [Member] | Energy derivative [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	68,353,000	79,625,000
Level 3 [Member] | Contingent Liabilities [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	($8,001,000)

Fair_Value_Measurements_Reconc

Fair Value Measurements - Reconciliation of Energy Derivative and Contingent Liabilities Measured at Fair Value (Detail) (Level 3 [Member], USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Beginning Balances	$71,624	$80,591
Settlements	-8,797	-19,644
Change in fair value, net of settlements	5,526	10,677
Ending Balances	68,353	71,624
Contingent Liabilities [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Beginning Balances	-8,001	-5,986
Settlements	8,001	'
Change in fair value, net of settlements	'	-2,015
Ending Balances	'	-8,001
Energy derivative [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Beginning Balances	79,625	86,577
Settlements	-16,798	-19,644
Change in fair value, net of settlements	5,526	12,692
Ending Balances	$68,353	$79,625

Fair_Value_Measurements_Carryi

Fair Value Measurements - Carrying Amounts and Fair Values of Company's Long Term Debt (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]	'	'
Carrying Amount	$1,249,218	$1,290,570
Fair Value	$1,165,119	$1,247,449

Income_Taxes_Components_of_Pro

Income Taxes - Components of Provision for Income Taxes (Detail) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Oct. 01, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Current	'	'	'	'	'
U.S. federal	'	'	'	'	'
State	'	'	'	'	'
Foreign	'	'	'	'	'
Current, total	'	'	'	'	'
Deferred	'	'	'	'	'
U.S. federal	'	'	2,961	'	'
State	'	'	'	'	'
Foreign	'	'	1,585	-3,604	689
Deferred, total	'	'	4,546	-3,604	809
Total income tax (benefit) provision	$11,314	($6,768)	$4,546	($3,604)	$689

Income_Taxes_Domestic_and_Fore

Income Taxes - Domestic and Foreign Components of Net Income (Loss) Before Income Tax (Benefit) Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]	'	'	'
U.S.	$4,022	($17,810)	$25,957
Foreign	10,596	830	638
Total	$14,618	($16,980)	$26,595

Income_Taxes_Reconciliation_of

Income Taxes - Reconciliation of Statutory U.S Federal Income Tax Rate to Effective Tax Rate (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Statutory U.S. federal tax rate	35.00%	35.00%	35.00%
Book/tax basis difference	'	27.20%	'
Partnership income not subject to taxes	'	-40.90%	-32.40%
Adjustment for income in non-taxable entities allocable to noncontrolling interest	16.50%	'	'
Foreign rate difference	'	'	'
Tax rate differential on pre-tax book income, other	2.10%	'	'
Valuation allowance	187.20%	'	'
Other	3.10%	'	'
ARRA Section 1603 grant-basis reduction deferred tax assets	-223.70%	'	'
Effective income tax rate	31.10%	21.30%	2.60%
Domestic [Member]	'	'	'
Schedule Of Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Permanent book/tax differences (domestic only)	-2.20%	'	'
Puerto Rico [Member]	'	'	'
Schedule Of Effective Income Tax Rate Reconciliation [Line Items]	'	'	'
Local tax on branch profits/(losses)-Puerto Rico	13.10%	'	'

Income_Taxes_Components_of_Def

Income Taxes - Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Deferred tax assets/liabilities-current	'	'
Other current deferred tax assets and liabilities	$2,399	'
Basis difference in derivatives	2,835	'
Total gross deferred tax assets/(liabilities)	5,234	'
Less: valuation allowance	-4,661	'
Total net deferred tax assets/(liabilities)-current	573	'
Deferred tax assets/(liabilities)-non-current:	'	'
Property, plant and equipment	-36,548	-47,894
Basis difference in foreign subsidiaries	40,097	'
Partnership interest	-4,917	'
Lease Hatchet Ridge	29,314	'
Asset retirement obligation	4,649	'
Equity method	3,794	'
Unrealized loss on derivatives	-5,830	'
Net operating loss carryforwards	61,441	45,302
Other non current deferred tax assets and liabilities	-4,595	-690
Change in tax status	'	4,599
Accruals not currently deductible	'	443
Total gross deferred tax assets/(liabilities)-non-current	87,405	1,760
Less: valuation allowance	-95,318	-482
Total net deferred tax assets/(liabilities)-non-current	-7,913	1,278
Total net deferred tax assets/(liabilities)	($7,340)	$1,278

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]	'	'	'
Net change in valuation allowance	'	$99.50	'
Limitation on set off of net operating loss	'	'Internal Revenue Code Section 382 places a limitation ( the bSection 382 Limitationb) on the amount of taxable income that can be offset by net operating loss (bNOLb) carryforwards after a change in control (generally greater than 50% change in ownership) of a loss corporation.	'
Unrecognized tax benefits	0	0	'
Significant change in unrecognized tax benefits is reasonably possible, amount	0	0	'
Special tax rate related to tax holiday	'	4.00%	'
Income tax holiday, termination date	'	'For a 25 year period and is scheduled to terminate on December 31, 2036.	'
Tax holiday impact, decrease in foreign deferred tax benefit	'	0.2	'
Tax holiday on net income per diluted share	'	$0.01	'
Contribution Transactions [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Net change in valuation allowance	'	79.3	'
Domestic [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Net change in valuation allowance	20.2	'	'
Net operating loss carryforwards	77.6	77.6	77.8
Net operating loss carryforwards, beginning expiry year	'	'2033	'2033
State [Member]	'	'	'
Income Taxes [Line Items]	'	'	'
Net operating loss carryforwards	$77.60	$77.60	$77.80
Net operating loss carryforwards, beginning expiry year	'	'2033	'2033

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013
			Board of Directors [Member]	Board of Directors [Member]
			Class A common stock [Member]	Class A common stock [Member]
Changes In Equity And Comprehensive Income Line Items [Line Items]	'	'	'	'
Common stock voting rights	'While each Class A and Class B share have one vote on all matters submitted to a vote of the Company's stockholders, Class B shares have no rights to dividends or distributions (other than upon liquidation).	'	'	'
Conversion of common stock shares	'All of the outstanding Class B shares will automatically convert, on a one-for-one basis, into Class A shares. Other than upon occurrence of the Conversion Event, there are no conversion rights attaching to the Class B shares.	'	'	'
Common stock, cash dividend declared	'	'	$0.31	$1.25
Dividends declared date	'	'	'	30-Nov-13
Dividend payment date	30-Jan-14	'	'	'
Dividend payment, date of stockholders record	31-Dec-13	'	'	'
Preferred stock, authorized	100,000,000	'	'	'
Preferred stock, issued	0	0	'	'
Preferred stock, outstanding	0	0	'	'

Equity_Incentive_Award_Plan_Ad

Equity Incentive Award Plan - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Stock-based compensation expense	($263,000)	$511,000	'
2013 Plan [Member] | Class A common stock [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Aggregate number of shares available for issuance	2,468,557	2,468,557	'
2013 Plan [Member] | Stock Options [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of shares authorized to be issued under plan	'	'	3,000,000
Stock options granted	444,823	444,823	'
Closing price per share on last trading day	$30.31	$30.31	'
Unrecorded stock-based compensation expense	1,700,000	1,700,000	'
Weighted-average period for amortization	'	'2 years 9 months 18 days	'
2013 Plan [Member] | Restricted stock awards [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of RSAs granted	86,620	'	'
Restricted stock awards vested, weighted average grant date fair value	$24.15	$200,000	'
Stock-based compensation expense	'	500,000	'
Unrecorded stock-based compensation expense	$1,700,000	$1,700,000	'
Weighted-average period for amortization	'	'2 years 9 months 18 days	'
2013 Plan [Member] | Employee [Member] | Restricted stock awards [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of RSAs granted	'	83,183	'
2013 Plan [Member] | Director [Member] | Restricted stock awards [Member]	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'
Number of RSAs granted	'	3,437	'

Equity_Incentive_Award_Plan_Su

Equity Incentive Award Plan - Summary of Restricted Stock Awards Activity (Detail) (2013 Plan [Member], Restricted stock awards [Member], USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013
2013 Plan [Member] | Restricted stock awards [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of RSAs Outstanding, Beginning balance	'	'
Number of RSAs Outstanding, Granted	86,620	'
Number of RSAs Outstanding, Released	-9,424	'
Number of RSAs Outstanding, Repurchased for employee tax withholding	-934	'
Number of RSAs Outstanding, Ending balance	76,262	76,262
Weighted Average Grant Date Fair Value, Beginning balance	'	'
Weighted Average Grant Date Fair Value, Granted	$22.71	'
Weighted Average Grant Date Fair Value, Released	$24.15	$200,000
Weighted Average Grant Date Fair Value, Repurchased for employee tax withholding	$22.53	'
Weighted Average Grant Date Fair Value, Ending balance	$22.53	$22.53
Aggregate Intrinsic Value, Ending balance	$2,311,501	$2,311,501

Equity_Incentive_Award_Plan_Su1

Equity Incentive Award Plan - Summary Stock Option Activity (Detail) (2013 Plan [Member], Stock Options [Member], USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013
2013 Plan [Member] | Stock Options [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of Options Outstanding, Beginning balance	'	'
Number of Options Outstanding, Granted	444,823	444,823
Number of Options Outstanding, Vested	-37,069	'
Number of Options Outstanding, Exercised	'	'
Number of Options Outstanding, Expired	'	'
Number of Options Outstanding , Forfeited	'	'
Number of Options Outstanding, Ending balance	407,754	407,754
Number of Options Outstanding, Exercisable	37,069	37,069
Weighted Average Exercise Price, Beginning balance	'	'
Weighted Average Exercise Price, Granted	$22	'
Weighted Average Exercise Price, Vested	$22	'
Weighted Average Exercise Price, Exercised	'	'
Weighted Average Exercise Price, Expired	'	'
Weighted Average Exercise Price, Forfeited	'	'
Weighted Average Exercise Price, Ending balance	$22	$22
Weighted Average Exercise Price, Exercisable	$22	$22
Weighted Average Remaining Contractual Life (in years), Ending balance	'9 years 9 months 18 days	'
Weighted Average Remaining Contractual Life (in years), Exercisable	'9 years 9 months 18 days	'
Aggregate Intrinsic Value, Ending balance	$3,388,436	$3,388,436
Aggregate Intrinsic Value, Exercisable	$308,043	$308,043

Equity_Incentive_Award_Plan_Sc

Equity Incentive Award Plan - Schedule of Weighted Average Assumptions (Detail) (Stock Options [Member])	12 Months Ended
	Dec. 31, 2013
Stock Options [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Risk-free interest rate	1.68%
Expected life (in years)	'5 years 9 months 18 days
Expected volatility	36.00%
Expected dividend yield	5.70%

Earning_Per_Share_Schedule_of_

Earning Per Share - Schedule of Consolidated Statements of Operations Before and After IPO (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Revenue:

'

'

'

'

'

'

'

'

'

'

'

'

'

Electricity sales

$41,836,000

'

'

'

'

'

'

'

'

$131,434,000

$173,270,000

$101,835,000

$108,770,000

Energy derivative settlements

4,035,000

'

'

'

'

'

'

'

'

12,763,000

16,798,000

19,644,000

9,512,000

Unrealized loss on energy derivative

-4,916,000

'

'

'

'

'

'

'

'

-6,356,000

-11,272,000

'

'

Related party revenue

446,000

'

'

'

'

'

'

'

'

465,000

911,000

'

'

Other revenue

701,000

'

'

'

'

'

'

'

'

21,165,000

21,866,000

'

'

Total revenue

42,102,000

'

'

'

'

'

'

'

'

159,471,000

201,573,000

114,528,000

135,859,000

Cost of revenue:

'

'

'

'

'

'

'

'

'

'

'

'

'

Project expense

15,455,000

'

'

'

'

'

'

'

'

42,222,000

57,677,000

34,843,000

31,343,000

Depreciation and accretion

21,193,000

'

'

'

'

'

'

'

'

61,987,000

83,180,000

49,027,000

39,424,000

Total cost of revenue

36,648,000

'

'

'

'

'

'

'

'

104,209,000

140,857,000

83,870,000

70,767,000

Gross profit

5,454,000

21,471,000

26,222,000

8,294,000

10,086,000

-5,213,000

6,175,000

19,610,000

'

55,262,000

60,716,000

30,658,000

65,092,000

Total operating expenses

3,456,000

'

'

'

'

'

'

'

'

9,532,000

12,988,000

11,636,000

9,668,000

Operating income (loss)

1,998,000

'

'

'

'

'

'

'

'

45,730,000

47,728,000

19,022,000

55,424,000

Other expense

-10,217,000

'

'

'

'

'

'

'

'

-22,893,000

-33,110,000

-36,002,000

-28,829,000

Net (loss) income before income tax

-8,219,000

'

'

'

'

'

'

'

'

22,837,000

14,618,000

-16,980,000

26,595,000

Tax provision (benefit)

11,314,000

'

'

'

'

'

'

'

'

-6,768,000

4,546,000

-3,604,000

689,000

Net (loss) income

-19,533,000

4,244,000

43,988,000

-18,784,000

-4,455,000

-16,913,000

-575,000

8,567,000

29,605,000

29,605,000

10,072,000

-13,376,000

25,906,000

Net loss attributable to noncontrolling interest

-6,197,000

3,248,000

-359,000

-3,579,000

-1,147,000

-7,494,000

-2,928,000

4,480,000

'

-690,000

-6,887,000

-7,089,000

16,981,000

Net income (loss) attributable to controlling interest

-13,336,000

996,000

44,347,000

-15,205,000

-3,308,000

-9,419,000

2,353,000

4,087,000

'

30,295,000

16,959,000

-6,287,000

8,925,000

Earnings per share information:

'

'

'

'

'

'

'

'

'

'

'

'

'

Less: Net income attributable to controlling interest prior to the IPO on October 2, 2013

'

'

'

'

'

'

'

'

'

'

-30,295,000

'

'

Net loss attributable to controlling interest subsequent to the IPO

'

'

'

'

'

'

'

'

'

'

-13,336,000

'

'

Numerator for basic and diluted earnings (loss) per share:

'

'

'

'

'

'

'

'

'

'

'

'

'

Net earnings (loss)

'

'

'

'

'

'

'

'

'

'

-13,336,000

'

'

Less: dividends declared

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends common stock

-11,103,000

'

'

'

'

'

'

'

'

'

'

'

'

Undistributed earnings (loss)

'

'

'

'

'

'

'

'

'

'

-24,439,000

'

'

Weighted average number of shares:

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic and diluted common stock

'

'

'

'

'

'

'

'

'

'

51,003,056

'

'

Class A common stock [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Less: dividends declared

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends common stock

'

'

'

'

'

'

'

'

'

'

-11,103,000

'

'

Weighted average number of shares:

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic and diluted common stock

'

'

'

'

'

'

'

'

'

'

35,448,056

'

'

Calculation of basic and diluted earnings (loss) per share:

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends

'

'

'

'

'

'

'

'

'

'

$0.31

'

'

Undistributed loss

'

'

'

'

'

'

'

'

'

'

($0.48)

'

'

Basic and diluted loss per share

($0.17)

'

'

'

'

'

'

'

'

'

($0.17)

'

'

Class B common stock [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Less: dividends declared

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends common stock

'

'

'

'

'

'

'

'

'

'

'

'

'

Weighted average number of shares:

'

'

'

'

'

'

'

'

'

'

'

'

'

Basic and diluted common stock

'

'

'

'

'

'

'

'

'

'

15,555,000

'

'

Calculation of basic and diluted earnings (loss) per share:

'

'

'

'

'

'

'

'

'

'

'

'

'

Dividends

'

'

'

'

'

'

'

'

'

'

'

'

'

Undistributed loss

'

'

'

'

'

'

'

'

'

'

($0.48)

'

'

Basic and diluted loss per share

($0.48)

'

'

'

'

'

'

'

'

'

($0.48)

'

'

Geographic_Information_Summary

Geographic Information - Summary of Geographical Revenues and Assets (Detail) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2013	Oct. 01, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'
Revenue	$42,102,000	$159,471,000	$201,573,000	$114,528,000	$135,859,000
Property, Plant and Equipment, net	1,476,142,000	'	1,476,142,000	1,668,302,000	'
Geographical Information [Member]	'	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'
Revenue	'	'	201,573,000	114,528,000	135,859,000
Property, Plant and Equipment, net	1,476,142,000	'	1,476,142,000	1,668,302,000	'
Geographical Information [Member] | United States [Member]	'	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'
Revenue	'	'	161,505,000	73,089,000	103,773,000
Property, Plant and Equipment, net	1,210,319,000	'	1,210,319,000	1,367,149,000	'
Geographical Information [Member] | Canada [Member]	'	'	'	'	'
Revenues from External Customers and Long-Lived Assets [Line Items]	'	'	'	'	'
Revenue	'	'	40,068,000	41,439,000	32,086,000
Property, Plant and Equipment, net	$265,823,000	'	$265,823,000	$301,153,000	'

Commitments_Contingencies_and_2

Commitments, Contingencies and Warranties - Additional Information (Detail) (USD $)

12 Months Ended

0 Months Ended

12 Months Ended

12 Months Ended

12 Months Ended

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 20, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Blade manufacturer [Member]

Panhandle 2 [Member]

Maximum [Member]

Pattern santa Isabel LLC [Member]

Turbines [Member]

Turbines [Member]

Turbines [Member]

Turbines [Member]

Construction [Member]

Construction [Member]

Power purchase agreements [Member]

Power purchase agreements [Member]

Power purchase agreements [Member]

Project Finance Agreements [Member]

Project Finance Agreements [Member]

MW

Project

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Revolving Credit Facility [Member]

Other Commitments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Power purchase agreements termination period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'2025

'2039

'

'

Irrevocable letters of credit

'

'

'

'

'

'

'

'

'

'

'

'

'

$57,200,000

'

'

$91,800,000

$44,800,000

Number of operating projects

'

'

'

'

'

'

'

6

'

'

'

'

'

'

'

'

'

'

Term of power purchase agreement

'

'

'

'

'

'

'

'

'

'2 years

'5 years

'

'

'

'

'

'

'

Annualized base fees per year

19,400,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Contingent purchase price obligations

0

8,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecorded contingent purchase price obligations

4,700,000

2,800,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Operating leases, Rent expense

6,100,000

4,200,000

4,600,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Purchase commitments, outstanding

4,100,000

5,100,000

'

'

'

'

'

0

1,700,000

'

'

0

22,300,000

'

'

'

'

'

Ownership interest

'

'

'

'

80.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

Power generation capacity

'

'

'

'

182

'

'

'

'

'

'

'

'

'

'

'

'

'

Business acquisition price

'

'

'

'

122,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Tax indemnifications liability

'

'

'

'

'

'

7,200,000

'

'

'

'

'

'

'

'

'

'

'

Liquidating damages or bonus

'

0

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warranty settlements for liquidated damage payments

21,900,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Warranty settlements

'

'

'

24,100,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Future refund of liquidated damage

'

'

'

'

'

$2,200,000

'

'

'

'

'

'

'

'

'

'

'

'

Commitments_Contingencies_and_3

Commitments, Contingencies and Warranties - Schedule of Turbine Operations and Maintenance Commitments (Detail) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]	'
2014	$16,465
2015	3,845
2016	2,188
2017	1,965
2018	55
Thereafter	591
Total	$25,109

Commitments_Contingencies_and_4

Commitments, Contingencies and Warranties - Schedule of Future Minimum Payments Related to Land Leases (Detail) (USD $)	Dec. 31, 2013
In Thousands, unless otherwise specified
Commitments And Contingencies Disclosure [Abstract]	'
2014	$3,713
2015	3,717
2016	3,725
2017	3,731
2018	3,738
Thereafter	91,876
Total	$110,500

Related_Party_Transactions_Add

Related Party Transactions - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

Dec. 31, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 20, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 20, 2013

Dec. 20, 2013

Panhandle 2 [Member]

Indirect Guarantee of Indebtedness [Member]

Guarantee Obligation by PEG LP [Member]

Pattern Development [Member]

Pattern Development [Member]

Pattern Energy Group LP [Member]

Grand [Member]

MW

Panhandle 2 [Member]

MW

Related Party Transaction [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of service fee of direct costs

'

'

5.00%

'

'

'

'

'

'

'

'

'

Amounts payable for services and supplies

'

'

'

'

'

'

'

'

$1,200,000

$200,000

'

'

Letters-of-credit outstanding

'

'

'

'

'

'

'

'

0

0

'

'

Guarantee for payment obligations

14,000,000

'

14,000,000

'

'

'

20,000,000

'

'

'

'

'

Remaining credit facility

'

'

'

'

'

'

'

6,000,000

'

'

'

'

Ownership interest

'

'

'

'

'

80.00%

'

'

'

'

80.00%

'

Power generation capacity

'

'

'

'

'

182

'

'

'

'

182

'

Business acquisition price

'

'

'

'

'

122,900,000

'

'

'

'

122,900,000

79,500,000

Electric power purchase contract expiration

'

'

'

'

'

'

'

'

'

'

'2014

'

Business acquisition, percentage of equity interest

'

'

'

'

'

'

'

'

'

'

'

45.00%

Business acquisition, contingent payment

'

'

'

'

'

'

'

'

'

'

'

4,700,000

Management fees

446,000

465,000

911,000

'

'

'

'

'

'

'

'

'

Related party receivable

200,000

'

200,000

'

'

'

'

'

'

'

'

'

Employer contribution, percentage

'

'

5.00%

'

'

'

'

'

'

'

'

'

Employer contribution, amount

'

'

$100,000

$0

$0

'

'

'

'

'

'

'

Related_Party_Transactions_All

Related Party Transactions - Allocated Costs Included in Combined Statement of Operations (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transactions [Abstract]	'	'	'
Project expense	$1,995	$1,998	$1,139
General and administrative	8,169	10,604	8,098
Management Services Agreement expense	851	'	'
Management Services Agreement income	-665	'	'
Other income	-551	-210	-199
Total	$8,948	$12,392	$9,038

Selected_Quarterly_Financial_D2

Selected Quarterly Financial Data - Summary of Quarterly Consolidated Statements of Operations (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Schedule Of Quarterly Financial Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue

$41,767,000

$57,257,000

$58,712,000

$43,837,000

$34,345,000

$16,903,000

$24,939,000

$38,341,000

'

'

'

'

'

Gross profit (loss)

5,454,000

21,471,000

26,222,000

8,294,000

10,086,000

-5,213,000

6,175,000

19,610,000

'

55,262,000

60,716,000

30,658,000

65,092,000

Net (loss) income

-19,533,000

4,244,000

43,988,000

-18,784,000

-4,455,000

-16,913,000

-575,000

8,567,000

29,605,000

29,605,000

10,072,000

-13,376,000

25,906,000

Net (loss) income attributable to noncontrolling interest

-6,197,000

3,248,000

-359,000

-3,579,000

-1,147,000

-7,494,000

-2,928,000

4,480,000

'

-690,000

-6,887,000

-7,089,000

16,981,000

Net (loss) income attributable to controlling interest

($13,336,000)

$996,000

$44,347,000

($15,205,000)

($3,308,000)

($9,419,000)

$2,353,000

$4,087,000

'

$30,295,000

$16,959,000

($6,287,000)

$8,925,000

Class A common stock [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Quarterly Financial Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Earnings per share-basic and diluted

($0.17)

'

'

'

'

'

'

'

'

'

($0.17)

'

'

Class B common stock [Member]

'

'

'

'

'

'

'

'

'

'

'

'

'

Schedule Of Quarterly Financial Information [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Earnings per share-basic and diluted

($0.48)

'

'

'

'

'

'

'

'

'

($0.48)

'

'

Condensed_Financial_Informatio

Condensed Financial Information of Parent Balance Sheets (Detail) (USD $)	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current assets:	'	'	'	'	'
Cash and cash equivalents	$103,569,000	'	$17,574,000	$47,672,000	$8,928,000
Related party receivable	167,000	'	'	'	'
Prepaid expenses and other current assets	13,927,000	'	13,794,000	'	'
Total current assets	154,579,000	'	113,567,000	'	'
Investments in subsidiaries	107,055,000	'	36,218,000	'	'
Net deferred tax assets	2,017,000	'	4,940,000	'	'
Total assets	1,903,631,000	'	2,035,730,000	'	'
Current liabilities:	'	'	'	'	'
Accounts payable and other accrued liabilities	15,550,000	'	7,750,000	'	'
Related party payable	1,245,000	'	198,000	'	'
Dividend payable	11,103,000	'	'	'	'
Total current liabilities	96,619,000	'	234,434,000	'	'
Net deferred tax liabilities	9,930,000	'	3,662,000	'	'
Total liabilities	1,335,627,000	'	1,446,318,000	'	'
Equity:	'	'	'	'	'
Additional paid-in capital	489,388,000	'	1,000	'	'
Capital	'	'	545,471,000	'	'
Accumulated income (loss)	-13,336,000	'	2,903,000	'	'
Accumulated other comprehensive loss	-8,353,000	'	-34,264,000	-35,610,000	-9,537,000
Total equity	568,004,000	569,828,000	589,412,000	446,698,000	335,944,000
Total liabilities and equity	1,903,631,000	'	2,035,730,000	'	'
Class A common stock [Member]	'	'	'	'	'
Equity:	'	'	'	'	'
Class A common stock, $0.01 par value per share: 500,000,000 shares authorized; 35,530,786 and 100 shares issued and outstanding as of December 31, 2013 and 2012, respectively	355,000	'	'	'	'
Class B common stock [Member]	'	'	'	'	'
Equity:	'	'	'	'	'
Class A common stock, $0.01 par value per share: 500,000,000 shares authorized; 35,530,786 and 100 shares issued and outstanding as of December 31, 2013 and 2012, respectively	156,000	'	'	'	'
Pattern Energy Group Inc	'	'	'	'	'
Current assets:	'	'	'	'	'
Cash and cash equivalents	75,776,000	'	1,000	'	'
Related party receivable	1,000,000	'	'	'	'
Prepaid expenses and other current assets	446,000	'	'	'	'
Total current assets	77,222,000	'	1,000	'	'
Investments in subsidiaries	407,271,000	'	514,117,000	'	'
Net deferred tax assets	573,000	'	'	'	'
Total assets	485,066,000	'	514,118,000	'	'
Current liabilities:	'	'	'	'	'
Accounts payable and other accrued liabilities	4,513,000	'	7,000	'	'
Related party payable	667,000	'	'	'	'
Dividend payable	11,103,000	'	'	'	'
Total current liabilities	16,283,000	'	7,000	'	'
Net deferred tax liabilities	573,000	'	'	'	'
Total liabilities	16,856,000	'	7,000	'	'
Equity:	'	'	'	'	'
Additional paid-in capital	461,828,000	'	1,000	'	'
Capital	'	'	551,109,000	'	'
Accumulated income (loss)	14,224,000	'	-2,735,000	'	'
Accumulated other comprehensive loss	-8,353,000	'	-34,264,000	'	'
Total equity	468,210,000	'	514,111,000	'	'
Total liabilities and equity	485,066,000	'	514,118,000	'	'
Pattern Energy Group Inc | Class A common stock [Member]	'	'	'	'	'
Equity:	'	'	'	'	'
Class A common stock, $0.01 par value per share: 500,000,000 shares authorized; 35,530,786 and 100 shares issued and outstanding as of December 31, 2013 and 2012, respectively	355,000	'	'	'	'
Pattern Energy Group Inc | Class B common stock [Member]	'	'	'	'	'
Equity:	'	'	'	'	'
Class A common stock, $0.01 par value per share: 500,000,000 shares authorized; 35,530,786 and 100 shares issued and outstanding as of December 31, 2013 and 2012, respectively	$156,000	'	'	'	'

Condensed_Financial_Informatio1

Condensed Financial Information of Parent Balance Sheets (Parenthetical) (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Class A common stock [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	35,530,786	100
Common stock, shares outstanding	35,530,786	100
Class B common stock [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Common stock, par value	$0.01	'
Common stock, shares authorized	20,000,000	'
Common stock, shares issued	15,555,000	'
Common stock, shares outstanding	15,555,000	'
Pattern Energy Group Inc | Class A common stock [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	35,530,786	100
Common stock, shares outstanding	35,530,786	100
Pattern Energy Group Inc | Class B common stock [Member]	'	'
Condensed Financial Statements, Captions [Line Items]	'	'
Common stock, par value	$0.01	'
Common stock, shares authorized	20,000,000	'
Common stock, shares issued	15,555,000	'
Common stock, shares outstanding	15,555,000	'

Condensed_Financial_Informatio2

Condensed Financial Information of Parent Statements of Operations and Comprehensive Income (Loss) (Detail) (USD $)

3 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2012

Dec. 31, 2013

Pattern Energy Group Inc

Pattern Energy Group Inc

Condensed Financial Statements, Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue

$42,102,000

'

'

'

'

'

'

'

'

$159,471,000

$201,573,000

$114,528,000

$135,859,000

'

'

Expenses

3,456,000

'

'

'

'

'

'

'

'

9,532,000

12,988,000

11,636,000

9,668,000

7,000

3,630,000

Operating income (loss)

1,998,000

'

'

'

'

'

'

'

'

45,730,000

47,728,000

19,022,000

55,424,000

-7,000

-3,630,000

Other income (expense):

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity in earnings (loss) from subsidiaries

'

'

'

'

'

'

'

'

'

'

7,846,000

-40,000

-205,000

-2,728,000

20,487,000

Related party income

'

'

'

'

'

'

'

'

'

'

665,000

'

'

'

665,000

Other expense, net

'

'

'

'

'

'

'

'

'

'

2,496,000

1,320,000

1,125,000

'

-563,000

Other income (expense)

-10,217,000

'

'

'

'

'

'

'

'

-22,893,000

-33,110,000

-36,002,000

-28,829,000

-2,728,000

20,589,000

Net income (loss) before income tax

-8,219,000

'

'

'

'

'

'

'

'

22,837,000

14,618,000

-16,980,000

26,595,000

-2,735,000

16,959,000

Tax (benefit) provision

-11,314,000

'

'

'

'

'

'

'

'

6,768,000

-4,546,000

3,604,000

-689,000

'

'

Net income (loss)

-13,336,000

996,000

44,347,000

-15,205,000

-3,308,000

-9,419,000

2,353,000

4,087,000

'

30,295,000

16,959,000

-6,287,000

8,925,000

-2,735,000

16,959,000

Other comprehensive income (loss), net of tax

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Foreign currency translation, net of tax

'

'

'

'

'

'

'

'

'

'

-8,309,000

2,749,000

-2,406,000

777,000

-8,309,000

Effective portion of change in fair market value of derivatives, net of tax

'

'

'

'

'

'

'

'

'

'

36,875,000

-11,170,000

-23,667,000

1,099,000

31,787,000

Proportionate share of equity investee's other comprehensive loss, net of tax

'

'

'

'

'

'

'

'

'

'

-2,473,000

1,475,000

'

'

2,473,000

Total other comprehensive income (loss), net of tax

6,847,000

'

'

'

'

'

'

'

24,192,000

'

31,039,000

-9,896,000

-26,073,000

1,876,000

25,951,000

Comprehensive income (loss)

'

'

'

'

'

'

'

'

'

'

$42,910,000

($15,399,000)

($11,013,000)

($859,000)

$42,910,000

Condensed_Financial_Informatio3

Condensed Financial Information of Parent Consolidated Statements of Cash Flows (Detail) (USD $)	3 Months Ended		12 Months Ended			3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012	Dec. 31, 2013
						Pattern Energy Group Inc	Pattern Energy Group Inc
Operating activities	'	'	'	'	'	'	'
Net income (loss)	$19,533,000	$4,455,000	($10,072,000)	$13,376,000	($25,906,000)	($2,735,000)	$16,959,000
Adjustments to reconcile net income (loss) to net cash used in operating activities:	'	'	'	'	'	'	'
Stock-based compensation	-263,000	'	511,000	'	'	'	511,000
Equity in (earnings) loss from subsidiaries	'	'	-7,846,000	40,000	205,000	2,728,000	-20,487,000
Changes in operating assets and liabilities:	'	'	'	'	'	'	'
Prepaid expenses and other current assets	13,927,000	13,794,000	13,927,000	13,794,000	'	'	446,000
Accounts payable and other accrued liabilities	-15,550,000	-7,750,000	-15,550,000	-7,750,000	'	-7,000	-4,513,000
Related party receivable/payable	'	'	190,000	-100,000	54,000	'	-1,007,000
Net cash used in operating activities	'	'	78,152,000	35,051,000	46,930,000	'	-4,377,000
Investing activities	'	'	'	'	'	'	'
Distributions from subsidiaries	'	'	'	'	'	'	233,226,000
Contributions to subsidiaries	'	'	'	'	'	'	-172,130,000
Net cash provided by (used in) investing activities	'	'	72,391,000	-638,953,000	-340,977,000	'	61,096,000
Financing activities	'	'	'	'	'	'	'
Repurchase of shares for employee tax withholding	'	'	'	'	'	'	-24,000
Capital contributions	'	'	32,679,000	281,519,000	232,277,000	1,000	32,678,000
Proceeds from IPO, net of expenses	'	'	317,926,000	'	'	'	317,926,000
Capital distributions	'	'	-98,886,000	-114,236,000	-114,198,000	'	-98,884,000
Capital distributions-Contribution Transactions	'	'	-232,640,000	'	'	'	-232,640,000
Net cash (used in) provided by financing activities	'	'	-63,401,000	573,167,000	331,336,000	1,000	19,056,000
Net change in cash and cash equivalents	'	'	85,995,000	-30,098,000	38,744,000	1,000	75,775,000
Cash and cash equivalents - Beginning of period	'	'	17,574,000	47,672,000	8,928,000	'	1,000
Cash and cash equivalents - End of period	103,569,000	17,574,000	103,569,000	17,574,000	47,672,000	1,000	75,776,000
Schedule of non-cash activities	'	'	'	'	'	'	'
Investments in subsidiaries	$107,055,000	$36,218,000	$107,055,000	$36,218,000	'	$514,117,000	$407,271,000

Statement_of_Financial_Positio

Statement of Financial Position (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
	USD ($)	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
					CAD	CAD	CAD	CAD
Current assets	'	'	'	'	'	'	'	'
Cash and cash equivalents	$103,569,000	$17,574,000	$47,672,000	$8,928,000	139,346	415,032	294,790	'
Restricted cash (note 3)	'	'	'	'	26,888,466	'	'	'
Sales tax recoverable	'	'	'	'	13,590,640	260,784	'	'
Other current assets (note 4)	13,927,000	13,794,000	'	'	1,515,511	54,527	'	'
Total current assets	154,579,000	113,567,000	'	'	42,133,963	730,343	'	'
Non-current assets	'	'	'	'	'	'	'	'
Restricted cash (note 3)	32,636,000	13,904,000	'	'	'	5,400,000	'	'
Advance payment	'	44,150,000	'	'	19,520,025	'	'	'
Deferred development costs (note 5)	'	26,544,000	'	'	'	32,334,346	'	'
Construction-in-progress (note 5)	'	6,081,000	'	'	625,636,458	'	'	'
Property, plant and equipment - net of accumulated depreciation of $86,934 (2012 - $47,582) (note 6)	1,476,142,000	1,668,302,000	'	'	115,915	82,188	'	'
Intangible assets - net of accumulated amortization of $592,315 (2012 - $385,980) (note 7)	'	'	'	'	430,584	82,388	135,343	'
Deferred financing costs - net of accumulated amortization of $1,056,079 (2012 - $nil)	35,792,000	42,654,000	'	'	19,361,860	'	'	'
Derivative assets (note 12)	82,167,000	62,895,000	'	'	26,757,264	'	'	'
Total assets	1,903,631,000	2,035,730,000	'	'	733,956,069	38,629,265	'	'
Current liabilities	'	'	'	'	'	'	'	'
Accounts payable and accrued liabilities	'	'	'	'	43,155,372	712,771	'	'
Current portion of construction facility loan (note 9)	'	'	'	'	1,914,367	'	'	'
Current portion of long-term contingent liabilities (note 14)	'	'	'	'	1,564,600	1,346,000	'	'
Derivative liability - current portion (note 12)	16,171,000	13,462,000	'	'	7,814,992	'	'	'
Other current liabilities (note 8)	'	'	'	'	1,030,657	'	'	'
Total current liabilities	96,619,000	234,434,000	'	'	55,479,988	2,058,771	'	'
Non-current liabilities	'	'	'	'	'	'	'	'
Construction facility loan (note 9)	'	'	'	'	542,717,827	'	'	'
Long-term contingent liabilities (note 14)	'	'	'	'	9,500,000	1,064,600	'	'
Asset retirement obligation (note 11)	20,834,000	19,056,000	10,342,000	9,365,000	5,833,484	'	'	'
Total liabilities	1,335,627,000	1,446,318,000	'	'	613,531,299	3,123,371	'	'
Partners' capital	'	'	'	'	'	'	'	'
Contributions (note 10)	'	'	'	'	103,164,191	35,440,000	22,420,000	'
Accumulated net income	-13,336,000	2,903,000	'	'	17,260,579	65,894	'	'
Partners capitals	'	'	'	'	120,424,770	35,505,894	22,420,000	'
Liabilities and Partners capital	'	'	'	'	733,956,069	38,629,265	'	'

Statement_of_Financial_Positio1

Statement of Financial Position (Parenthetical) (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]
			CAD	CAD
Condensed Balance Sheet Statements, Captions [Line Items]	'	'	'	'
Property, plant and equipment, accumulated depreciation	$179,778,000	$100,247,000	86,934	47,582
Intangible assets, accumulated amortization	'	'	592,315	385,980
Deferred financing costs, accumulated amortization	$16,225,000	$9,311,000	1,056,079	'

Statement_of_Operations_and_Co

Statement of Operations and Comprehensive Income (Detail)

3 Months Ended

9 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

CAD

CAD

CAD

Condensed Income Statements, Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Revenue

$42,102,000

'

'

'

'

'

'

'

$159,471,000

$201,573,000

$114,528,000

$135,859,000

'

'

'

Operating expenses

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Professional fees

'

'

'

'

'

'

'

'

'

'

'

'

-341,110

'

'

General and administrative

'

'

'

'

'

'

'

'

'

-4,819,000

-858,000

-866,000

-320,281

-27,048

'

General and administrative - related party

'

'

'

'

'

'

'

'

'

-8,169,000

-10,604,000

-8,098,000

-555,588

'

'

Depreciation and amortization

-21,193,000

'

'

'

'

'

'

'

-61,987,000

-83,180,000

-49,027,000

-39,424,000

-32,863

'

'

Operating income (loss)

1,998,000

'

'

'

'

'

'

'

45,730,000

47,728,000

19,022,000

55,424,000

-1,249,842

-27,048

'

Unrealized gain on derivatives (note 12)

'

'

'

'

'

'

'

'

'

15,601,000

-4,953,000

-345,000

18,942,272

'

'

Other (expenses) income

-10,217,000

'

'

'

'

'

'

'

-22,893,000

-33,110,000

-36,002,000

-28,829,000

-497,745

92,942

'

Net income (loss)

($13,336,000)

$996,000

$44,347,000

($15,205,000)

($3,308,000)

($9,419,000)

$2,353,000

$4,087,000

$30,295,000

$16,959,000

($6,287,000)

$8,925,000

17,194,685

65,894

'

Statement_of_Changes_in_Partne

Statement of Changes in Partners' Capital (Detail)

3 Months Ended

9 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Sep. 30, 2013

Oct. 01, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

USD ($)

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

CAD

CAD

CAD

Partners' Capital [Member]

Partners' Capital [Member]

Partners' Capital [Member]

Accumulated Income (Deficit) [Member]

Accumulated Income (Deficit) [Member]

Accumulated Income (Deficit) [Member]

CAD

CAD

CAD

CAD

CAD

CAD

Condensed Financial Statements, Captions [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance at January 1, 2011

'

'

'

'

'

'

'

'

'

'

'

'

'

35,505,894

22,420,000

'

35,440,000

22,420,000

'

65,894

'

'

Cash initial contribution

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10,000

'

'

10,000

'

'

'

Cash contribution

'

'

'

'

'

'

'

'

32,677,000

'

'

281,519,000

232,277,000

9,016,022

13,020,000

22,410,000

9,016,022

13,020,000

22,410,000

'

'

'

Cash distribution

-232,640,000

'

'

'

'

'

'

'

-106,060,000

'

'

-115,534,000

-121,356,000

-21,393,091

'

'

-21,393,091

'

'

'

'

'

Non-cash contribution

'

'

'

'

'

'

'

'

'

'

'

'

'

80,101,260

'

'

80,101,260

'

'

'

'

'

Net income

-19,533,000

4,244,000

43,988,000

-18,784,000

-4,455,000

-16,913,000

-575,000

8,567,000

29,605,000

29,605,000

10,072,000

-13,376,000

25,906,000

17,194,685

65,894

'

'

'

'

17,194,685

65,894

'

Balance at December 31, 2011

'

'

'

'

'

'

'

'

'

'

'

'

'

120,424,770

35,505,894

22,420,000

103,164,191

35,440,000

22,420,000

17,260,579

65,894

'

Statements_of_Cash_Flows_Detai

Statements of Cash Flows (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				CAD	CAD	CAD
Operating activities	'	'	'	'	'	'
Net income (loss) for the period	$10,072,000	($13,376,000)	$25,906,000	17,194,685	65,894	'
Adjustment to reconcile net income (loss) to net cash used in operating activities	'	'	'	'	'	'
Unrealized gain on derivatives	-15,601,000	4,953,000	345,000	-18,942,272	'	'
Non-cash activities	'	'	'	100,879	-38,984	'
Bad debt expense	'	'	'	300,000	'	'
Net cash provided by operating activities	78,152,000	35,051,000	46,930,000	-1,346,708	26,910	'
Investing activities	'	'	'	'	'	'
Consideration paid for the acquisition of project assets	'	'	'	-1,346,000	'	-15,215,910
Construction costs paid	'	'	'	-478,425,665	'	'
Purchase of property, plant and equipment and intangible assets	-123,517,000	-641,422,000	-392,212,000	-627,610	-178,184	-162,482
Deferred development costs paid	-528,000	-7,093,000	-17,777,000	'	-12,748,484	-1,346,818
Payment for restricted cash	66,517,000	28,431,000	9,988,000	-21,488,466	'	-5,400,000
Net cash provided by (used in) investing activities	72,391,000	-638,953,000	-340,977,000	-501,887,741	-12,926,668	-22,125,210
Financing activities	'	'	'	'	'	'
Partner contribution	'	'	'	9,016,022	'	'
Construction facility loan proceeds	'	'	'	535,753,771	'	'
Deferred financing costs paid	-294,000	-19,989,000	-17,001,000	-20,417,939	'	'
Distribution to partners	-98,886,000	-114,236,000	-114,198,000	-21,393,091	13,020,000	22,420,000
Net cash (used in) provided by financing activities	-63,401,000	573,167,000	331,336,000	502,958,763	13,020,000	22,420,000
Increase (decrease) in cash and cash equivalents during the period	85,995,000	-30,098,000	38,744,000	-275,686	120,242	294,790
Cash and cash equivalents - Beginning of period	17,574,000	47,672,000	8,928,000	415,032	294,790	'
Cash and cash equivalents - End of period	103,569,000	17,574,000	47,672,000	139,346	415,032	294,790
Supplemental non-cash activities disclosure	'	'	'	'	'	'
Transfer to Construction-in-progress from deferred development costs	'	'	'	32,334,346	'	'
Accrued construction costs	'	'	'	42,442,601	'	'
Non-monetary contribution from partners	'	'	'	80,101,260	'	'
Construction loan - capitalized interest	4,171,000	9,386,000	3,621,000	8,878,422	'	'
Depreciation and amortization	'	'	'	1,200,887	257,093	176,469
Community fund commitment	'	'	'	10,000,000	'	'

General_Information_Additional

General Information - Additional Information (Detail) (South Kent Wind LP [Member])	0 Months Ended	12 Months Ended
	Aug. 02, 2011	Dec. 31, 2013	Dec. 31, 2012
		MWh
Schedule Of Description Of Business [Line Items]	'	'	'
Ownership interest, limited partners	'	100.00%	100.00%
Power generation capacity	'	270	'
Sale percentage of electrical output	100.00%	'	'
Scenario, Forecast [Member]	'	'	'
Schedule Of Description Of Business [Line Items]	'	'	'
Number of wind turbine generators	'	124	'
PPA of project	'	'20 years	'
Samsung Renewable Energy Inc. [Member]	'	'	'
Schedule Of Description Of Business [Line Items]	'	'	'
Ownership interest, limited partners	'	'	49.99%
Pattern South Kent LP Holdings LP [Member]	'	'	'
Schedule Of Description Of Business [Line Items]	'	'	'
Ownership interest, limited partners	'	'	49.99%
South Kent Wind GP Inc. [Member]	'	'	'
Schedule Of Description Of Business [Line Items]	'	'	'
Ownership interest, limited partners	'	0.02%	0.02%

General_Information_Schedule_o

General Information - Schedule of Partnership's Ownership Interests (Detail) (South Kent Wind LP [Member])	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	100.00%	100.00%
SRE SKW LP Holdings LP [Member]	'	'
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	49.99%	'
Pattern Canada Operations Holdings ULC [Member]	'	'
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	49.99%	'
Samsung Renewable Energy Inc. [Member]	'	'
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	'	49.99%
Pattern South Kent LP Holdings LP [Member]	'	'
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	'	49.99%
South Kent Wind GP Inc. [Member]	'	'
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]	'	'
Partnerships ownership interests, percentage	0.02%	0.02%

Summary_of_Significant_Account5

Summary of Significant Accounting Policies - Additional Information (Detail) (South Kent Wind LP [Member], CAD)	12 Months Ended
	Dec. 31, 2013	Mar. 08, 2013	Dec. 31, 2012
South Kent Wind LP [Member]	'	'	'
Significant Accounting Policies [Line Items]	'	'	'
Deferred developing costs transferred	'	32,334,346	32,334,346
Costs incurred during development stage	17,369,038	'	'
Credit adjusted risk free interest rate	5.54%	'	'

Restricted_Cash_Components_of_

Restricted Cash - Components of Restricted Cash (Detail) (South Kent Wind LP [Member], CAD)	Dec. 31, 2013	Dec. 31, 2012
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted Cash	26,888,466	5,400,000
Security Deposit for Letter of Guarantee to Ontario Power Authority [Member] | Ontario [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted Cash	8,100,000	5,400,000
Security Deposit for Letter of Guarantee to Municipality of Chatham-Kent [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted Cash	2,614,000	'
Security Deposit for Letter of Guarantee - others [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted Cash	82,338	'
10% Holdback Account for Contractors [Member]	'	'
Restricted Cash and Cash Equivalents Items [Line Items]	'	'
Restricted Cash	16,092,128	'

Restricted_Cash_Components_of_1

Restricted Cash - Components of Restricted Cash (Parenthetical) (Detail) (South Kent Wind LP [Member])	12 Months Ended
	Dec. 31, 2013
South Kent Wind LP [Member]	'
Restricted Cash and Cash Equivalents Items [Line Items]	'
Percentage of holdback account for contractors	10.00%

Other_Current_Assets_Component

Other Current Assets - Components of Other Current Assets (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]
			CAD	CAD
Other Current Assets By Type [Line Items]	'	'	'	'
Mortgage debt receivable, net	'	'	828,386	'
Refundable deposit on COD	'	'	86,000	'
Prepaid expenses	10,132,000	7,202,000	484,477	15,544
Accrued interest income	'	'	116,648	38,983
Prepaid expenses and other current assets	$13,927,000	$13,794,000	1,515,511	54,527

Other_Current_Assets_Component1

Other Current Assets - Components of Other Current Assets (Parenthetical) (Detail) (South Kent Wind LP [Member], CAD)	Dec. 31, 2013
South Kent Wind LP [Member]	'
Other Current Assets By Type [Line Items]	'
Mortgage debt receivable, bad debt provision	300,000

Deferred_Development_Costs_and

Deferred Development Costs and Construction in Progress - Components of Deferred Development Costs and Construction in Progress (Detail)	Dec. 31, 2012	Dec. 31, 2013	Mar. 08, 2013	Dec. 31, 2012
	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
		CAD	CAD	CAD
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]	'	'	'	'
Deferred development costs	'	'	32,334,346	32,334,346
Construction in progress	$6,081,000	625,636,458	'	'

Deferred_Development_Costs_and1

Deferred Development Costs and Construction in Progress - Additional Information (Detail)	12 Months Ended						12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Mar. 08, 2013	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				CAD	CAD	CAD	Construction [Member]	Construction [Member]
							CAD	CAD
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Line Items]	'	'	'	'	'	'	'	'
Deferred development costs transferred	'	'	'	'	32,334,346	32,334,346	'	'
Capitalized interest	$4,171,000	$9,386,000	$3,621,000	8,878,422	'	'	12,583,514	'

Property_Plant_and_Equipment_P

Property, Plant and Equipment - Property, Plant and Equipment at Historical Cost (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
			CAD	CAD	Machinery and equipment [Member]	Machinery and equipment [Member]
					CAD	CAD
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'
Subtotal	$1,655,920,000	$1,768,549,000	202,849	129,770	202,849	129,770
Less: Accumulated depreciation	-179,778,000	-100,247,000	-86,934	-47,582	'	'
Property plant and equipment, net	$1,476,142,000	$1,668,302,000	115,915	82,188	'	'
Depreciable life	'	'	'	'	'5 years	'

Property_Plant_and_Equipment_A1

Property, Plant and Equipment - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				CAD	CAD	Deferred Development Costs [Member]	Deferred Development Costs [Member]
						CAD	CAD
Property, Plant and Equipment [Line Items]	'	'	'	'	'	'	'
Depreciation expense related to property, plant and equipment	$82,000,000	$48,300,000	$38,900,000	32,863	'	6,489	47,582

Intangible_Assets_Schedule_of_

Intangible Assets - Schedule of Intangible Assets (Detail) (South Kent Wind LP [Member], CAD)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
South Kent Wind LP [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Beginning net book value	82,388	135,343
Additions	554,531	178,184
Amortization expense	-206,335	-231,139
Closing net book value	430,584	82,388
Cost	1,022,899	468,368
Accumulated amortization	-592,315	-385,980
Net book value	430,584	82,388

Intangible_Assets_Additional_I

Intangible Assets - Additional Information (Detail) (South Kent Wind LP [Member], CAD)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]	'	'
Amortization	-206,335	-231,139
Deferred Development Costs [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Amortization	206,355	231,139

Other_Current_Liabilities_Comp

Other Current Liabilities - Components of Accounts Payable and Other Accrued Liabilities (Detail) (South Kent Wind LP [Member], CAD)	Dec. 31, 2013	Dec. 31, 2012
South Kent Wind LP [Member]	'	'
Accrued Expenses And Other Current Liabilities [Line Items]	'	'
Accrued expenses	856,084	'
Accrued interest - construction facility loan	174,573	'
Accounts payable and other accrued liabilities	1,030,657	'

Long_Term_Debt_Additional_Info1

Long Term Debt - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Mar. 08, 2013
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				CAD	CAD	Financial_Institution
Debt Instrument [Line Items]	'	'	'	'	'	'
Number of financial institutions	'	'	'	'	'	15
Credit facility agreement, description	'	'	'	'On March 8, 2013, the Partnership signed a credit facility agreement with a syndicate of lenders consisting of 15 different financial institutions for a term of construction period plus seven years at a rate of Canadian Dealer Offered Rate (CDOR) plus 2.5% per annum for the first four years and CDOR plus 2.75% per annum thereafter. The credit facilities under the agreement include a $683,817,047 construction facility, letter of credit facility and an interest rate hedge facility. The funds from these facilities will be utilized to finance the construction of the Project and to run the project operations thereafter.	'	'
Line of credit facility	'	'	'	683,817,047	'	'
Capitalized interest	$4,171,000	$9,386,000	$3,621,000	8,878,422	'	'

Long_Term_Debt_Schedule_of_Lon1

Long Term Debt - Schedule of Long Term Debt (Detail)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
			CAD	CAD	Construction credit facility [Member]	Construction credit facility [Member]
					CAD	CAD
Debt Instrument [Line Items]	'	'	'	'	'	'
Long term debt	$1,249,218,000	$1,290,570,000	544,632,194	'	544,632,194	'
Less: Current Portion	-48,851,000	-137,258,000	-1,914,367	'	'	'
Long term debt, noncurrent	$1,200,367,000	$1,153,312,000	542,717,827	'	'	'
Long term debt, Interest Rate	'	'	'	'	3.75%	'
Long term debt, Interest Type	'	'	'	'	'Variable	'
Long term debt, Loan type	'	'	'	'	'Project financing	'
Long term debt, Maturity	'	'	'	'	'March 8, 2021	'

Contributions_fromDistribution

Contributions from/Distribution to Joint Venture Partners - Schedule of Contributions from Distribution to Joint Venture Partners (Detail)

3 Months Ended

9 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

Dec. 31, 2013

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2011

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

Dec. 31, 2012

USD ($)

USD ($)

USD ($)

USD ($)

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

CAD

CAD

CAD

CAD

Jan. 3, 2013 [Member]

Jan. 11, 2013 [Member]

Feb. 5, 2013 [Member]

Feb. 22, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 7, 2013 [Member]

Mar. 8, 2013 [Member]

Feb. 22, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 7, 2013 [Member]

May 4, 2012 [Member]

August 31, 2012 [Member]

November 20, 2012 [Member]

November 28, 2012 [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

SRE SKW LP Holdings LP [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

Pattern Canada Operations Holdings ULC [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

South Kent Wind GP Inc. [Member]

CAD

CAD

CAD

CAD

Contribution One [Member]

Contribution Two [Member]

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

Jan. 3, 2013 [Member]

Jan. 11, 2013 [Member]

Feb. 5, 2013 [Member]

Mar. 7, 2013 [Member]

Mar. 8, 2013 [Member]

Feb. 22, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 7, 2013 [Member]

May 4, 2012 [Member]

August 31, 2012 [Member]

November 20, 2012 [Member]

November 28, 2012 [Member]

CAD

CAD

Jan. 3, 2013 [Member]

Jan. 11, 2013 [Member]

Feb. 5, 2013 [Member]

Mar. 7, 2013 [Member]

Mar. 8, 2013 [Member]

Feb. 22, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 7, 2013 [Member]

May 4, 2012 [Member]

August 31, 2012 [Member]

November 20, 2012 [Member]

November 28, 2012 [Member]

CAD

CAD

Jan. 3, 2013 [Member]

Jan. 11, 2013 [Member]

Feb. 5, 2013 [Member]

Feb. 22, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 6, 2013 [Member]

Mar. 7, 2013 [Member]

Mar. 8, 2013 [Member]

May 4, 2012 [Member]

August 31, 2012 [Member]

November 20, 2012 [Member]

November 28, 2012 [Member]

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

Contribution One [Member]

Contribution Two [Member]

CAD

CAD

CAD

CAD

CAD

CAD

CAD

CAD

Joint Ventures [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance

'

'

'

'

'

35,440,000

22,420,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

17,716,456

11,207,758

'

'

'

'

'

'

'

'

'

'

'

'

17,716,456

11,207,758

'

'

'

'

'

'

'

'

'

'

'

'

7,088

4,484

'

'

'

'

'

'

'

'

'

'

'

'

Subsequent cash distribution

-232,640,000

-106,060,000

-115,534,000

-121,356,000

'

-21,393,091

'

'

'

'

'

'

'

'

-2,252,525

-19,140,566

'

'

'

'

'

'

'

-10,694,406

'

'

'

'

-1,126,037

-9,568,369

'

'

'

'

'

'

'

-10,694,406

'

'

'

'

-1,126,037

-9,568,369

'

'

'

'

'

'

'

-4,279

'

'

'

'

'

'

'

-451

-3,828

'

'

'

'

Subsequent cash contribution

'

32,677,000

281,519,000

232,277,000

'

9,016,022

13,020,000

22,410,000

3,400,000

2,900,000

2,700,000

3,943

11,802

277

'

'

'

'

'

6,920,000

3,620,000

880,000

1,600,000

4,499,100

6,508,698

1,699,660

1,449,710

1,349,730

'

'

'

'

'

3,459,308

1,809,638

439,912

799,840

4,499,100

6,508,698

1,699,660

1,449,710

1,349,730

'

'

'

'

'

3,459,308

1,809,638

439,912

799,840

17,822

2,604

680

580

540

3,943

11,802

277

'

'

1,384

724

176

320

Non-cash contribution

'

'

'

'

79,950,417

80,101,260

'

'

'

'

'

'

'

'

'

'

19,713,686

59,000,000

1,387,574

'

'

'

'

40,050,630

'

'

'

'

'

'

9,856,843

29,500,000

693,787

'

'

'

'

40,050,630

'

'

'

'

'

'

9,856,843

29,500,000

693,787

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Balance

'

'

'

'

'

103,164,191

35,440,000

22,420,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

51,571,780

17,716,456

'

'

'

'

'

'

'

'

'

'

'

'

51,571,780

17,716,456

'

'

'

'

'

'

'

'

'

'

'

'

20,631

7,088

'

'

'

'

'

'

'

'

'

'

'

'

Contributions_fromDistribution1

Contributions from/Distribution to Joint Venture Partners - Additional Information (Detail) (South Kent Wind LP [Member], CAD)	1 Months Ended	12 Months Ended			0 Months Ended			12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Feb. 19, 2013	Feb. 19, 2013	Mar. 06, 2013	Dec. 31, 2013
			Mar. 7, 2013 [Member]	Mar. 6, 2013 [Member]	Pattern Energy [Member]	Pattern Energy [Member]	Pattern Energy [Member]	EPCO [Member]
					February 19, 2013 [Member]	Mar. 7, 2013 [Member]	Mar. 6, 2013 [Member]	Korea [Member]
Joint Ventures [Line Items]	'	'	'	'	'	'	'	'
Non-cash contribution	79,950,417	80,101,260	1,387,574	59,000,000	19,713,686	1,387,574	59,000,000	'
Partnership interest	'	'	'	'	'	'	'	20.00%

Asset_Retirement_Obligations_A1

Asset Retirement Obligations - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligations [Line Items]	'
Estimated asset retirement period	'20 years
Asset retirement obligations, description	'The Company's asset retirement obligations represent the estimated cost of decommissioning the turbines, removing above-ground installations and restoring the sites at a date that is 20 years from the commencement of commercial operation of the facility.
South Kent Wind LP [Member]	'
Asset Retirement Obligations [Line Items]	'
Estimated asset retirement period	'20 years
Asset retirement obligations, description	'The Partnership's asset retirement obligation represents the estimated cost of decommissioning the turbines, removing above-ground installations and restoring the sites at a date that is 20 years from the commencement of commercial operations.

Asset_Retirement_Obligations_R1

Asset Retirement Obligations - Reconciliation of Beginning and Ending Aggregate Carrying Amounts of Asset Retirement Obligations (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				CAD	CAD
Asset Retirement Obligation [Line Items]	'	'	'	'	'
Beginning asset retirement obligations	$19,056,000	$10,342,000	$9,365,000	'	'
Additions during the year	767,000	7,971,000	467,000	5,833,484	'
Accretion expense	1,183,000	684,000	553,000	'	'
Ending asset retirement obligations	$20,834,000	$19,056,000	$10,342,000	5,833,484	'

Derivative_Instruments_Additio1

Derivative Instruments - Additional Information (Detail) (South Kent Wind LP [Member], Interest rate swaps [Member])	Mar. 14, 2013
South Kent Wind LP [Member] | Interest rate swaps [Member]	'
Derivatives, Fair Value [Line Items]	'
Variable interest rate exchange for fixed interest rate payments	5.54%

Derivative_Instruments_Schedul1

Derivative Instruments - Schedule of Derivative Instruments Classified as Assets and Liabilities (Detail)	12 Months Ended									12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013	Dec. 31, 2013
	USD ($)	USD ($)	USD ($)	Undesignated Derivative Instruments [Member]	Undesignated Derivative Instruments [Member]	Undesignated Derivative Instruments [Member]	Undesignated Derivative Instruments [Member]	Undesignated Derivative Instruments [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				Derivative Assets (Liabilities) [Member]	Derivative Assets (Liabilities) [Member]	Derivative Assets (Liabilities) [Member]	Interest rate swaps [Member]	Interest rate swaps [Member]	CAD	Undesignated Derivative Instruments [Member]
				USD ($)	USD ($)	USD ($)	Derivative Assets (Liabilities) [Member]	Derivative Assets (Liabilities) [Member]		Interest rate swaps [Member]
							USD ($)	USD ($)		Derivative Assets (Liabilities) [Member]
							Instruments	Instruments		CAD
										Instruments
Derivatives, Fair Value [Line Items]	'	'	'	'	'	'	'	'	'	'
Quantity	'	'	'	'	'	'	6	6	'	13
Maturity Dates	'	'	'	'	'	'	30-Jun-30	30-Jun-30	'	31-Mar-32
Fair Market Value, Current Portion	$13,937,000	$17,177,000	'	$10,038,000	$15,197,000	$18,687,000	($3,899,000)	($1,980,000)	'	-7,814,992
Fair Market Value, Long-Term Portion	82,167,000	62,895,000	'	69,455,000	59,964,000	68,381,000	14,358,000	-2,931,000	26,757,264	26,757,264
Gain (loss) Recognized into Income	'	'	'	4,329,000	-11,904,000	17,232,000	15,367,000	-4,909,000	'	18,942,272
Gain (loss) Recognized in OCI	$36,875,000	($11,170,000)	($23,667,000)	'	'	'	'	'	'	'

Fair_Value_Measurements_Financ1

Fair Value Measurements - Financial Assets and (Liabilities) Measured on Recurring Basis (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Level 1 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 1 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
Level 2 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	4,141,000	-48,341,000
Level 2 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	3,460,000	-48,788,000
Level 3 [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	68,353,000	71,624,000
Level 3 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
South Kent Wind LP [Member] | Level 1 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'
South Kent Wind LP [Member] | Level 2 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	18,942,272	'
South Kent Wind LP [Member] | Level 3 [Member] | Interest rate swaps [Member]	'	'
Fair Value, Estimate Not Practicable, Financial Statement Captions [Line Items]	'	'
Financial assets and (liabilities)	'	'

Commitments_Contingencies_and_5

Commitments, Contingencies and Warranties - Additional Information (Detail)

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Mar. 08, 2013

Dec. 31, 2013

Apr. 17, 2013

Apr. 30, 2013

Dec. 31, 2013

Dec. 31, 2013

Aug. 02, 2011

Dec. 31, 2013

Dec. 31, 2012

USD ($)

USD ($)

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

South Kent Wind LP [Member]

CAD

Land Lease Agreement [Member]

Land Lease Agreement [Member]

Operational Incentive Agreement [Member]

Operational Incentive Agreement [Member]

Community Fund Agreement [Member]

Community Fund Agreement [Member]

APA [Member]

APA [Member]

Power purchase agreements [Member]

Power purchase agreements [Member]

Power purchase agreements [Member]

CAD

CAD

CAD

CAD

CAD

CAD

Northland Power Inc. [Member]

Suncor Energy Products Inc. [Member]

MWs

CAD

CAD

AnnualInstallments

USD ($)

USD ($)

Other Commitments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Initial agreement date

'

'

'

'

'

8-Mar-11

'

17-Apr-11

'

4-Mar-11

22-Mar-11

2-Aug-11

'

'

Contract capacity of power purchase agreement

'

'

'

'

'

'

'

'

'

'

'

270

'

'

Term of power purchase agreement

'

'

'

'

'

'

'

'

'

'

'

'20 years

'

'

Selling price per unit of output

'

'

'

'

'

'

'

'

'

'

'

135

'

'

Fixed portion percentage in selling price per unit

'

'

'

'

'

'

'

'

'

'

'

80.00%

'

'

Escalation portion percentage in selling price per unit

'

'

'

'

'

'

'

'

'

'

'

20.00%

'

'

Initial security per unit of contract capacity

'

'

'

'

'

'

'

'

'

'

'

0.02

'

'

Incremental security per unit of contract capacity

'

'

'

'

'

'

'

'

'

'

'

0.01

'

'

Letter of guarantee under power purchase agreement

'

'

'

'

'

'

'

'

'

'

'

'

8,100,000

5,400,000

Letter of guarantee due date

'

'

'

'

'

'

'

'

'

'

'

'

31-Jul-14

'

First amendment, agreement dates

'

'

'

'

'

'

'

'

'

'

'

'

'January 29, 2013 and August 22, 2013

'

Liability on Project reaches commercial operation under the power purchase agreement

'

'

'

'

'

'

'

'

'

675,000

389,600

'

'

'

Number of annual contributions liability

'

'

'

'

'

'

'

20

'

'

'

'

'

'

Initial contribution liability

'

'

'

'

'

'

'

1,000,000

'

'

'

'

'

'

Annual contributions liability

'

'

'

'

'

'

'

500,000

'

'

'

'

'

'

Total contributions liability

'

'

'

'

'

'

'

'

10,000,000

'

'

'

'

'

Initial contribution liability

'

'

'

'

'

1,078,996

'

'

'

'

'

'

'

'

Operational incentive payment per unit of de-rated capacity

'

'

'

'

'

'

0.02

'

'

'

'

'

'

'

Operational incentive payment

'

'

'

'

'

'

15,000,000

'

'

'

'

'

'

'

Capitalized lease payments and amortization of land options

'

'

'

713,605

177,184

'

'

'

'

'

'

'

'

'

Purchase commitments, outstanding

4,100,000

5,100,000

50,266,877

'

'

'

'

'

'

'

'

'

'

'

Contract commitment outstanding

'

'

23,967,910

'

'

'

'

'

'

'

'

'

'

'

Commitments_Contingencies_and_6

Commitments, Contingencies and Warranties - Schedule of Future Minimum Payments Related to Land Leases (Detail)	Dec. 31, 2013	Dec. 31, 2013
	USD ($)	South Kent Wind LP [Member]
		CAD
Product Royalty Future Minimum Payment Due [Line Items]	'	'
2014	$3,713,000	1,017,943
2015	3,717,000	1,222,133
2016	3,725,000	1,295,059
2017	3,731,000	1,302,068
2018	3,738,000	1,312,842
Thereafter	91,876,000	39,463,763
Total	$110,500,000	45,613,807

Related_Party_Transactions_Add1

Related Party Transactions - Additional Information (Detail)	3 Months Ended	9 Months Ended	12 Months Ended	0 Months Ended
	Dec. 31, 2013	Oct. 01, 2013	Dec. 31, 2013	Mar. 08, 2013	Mar. 08, 2013	Mar. 08, 2013
	USD ($)	USD ($)	USD ($)	South Kent Wind LP [Member]	South Kent Wind LP [Member]	South Kent Wind LP [Member]
				PAA [Member]	EPC Contract [Member]	MOMA [Member]
				CAD	CAD	CAD
Related Party Transaction Due From To Related Party [Line Items]	'	'	'	'	'	'
Annual fee cost	'	'	'	350,000	'	855,000
Annual fee payment, terms	'	'	'	'The fixed annual fee for the service is $350,000 retroactively pro-rated for the period from June 15, 2012 until the COD and thereafter the annual fee will be increased to $500,000.	'	'The fixed annual fee for the service is $855,000 pro-rated for the period from March 8, 2013 until the COD and thereafter the annual fee will be increased to $1,425,000 until the end of the term (20 years from the COD).
Annual management fee increased	'	'	'	500,000	'	1,425,000
Annual management fee term	'	'	'	'	'	'20 years
Payment from partnership	$446,000	$465,000	$911,000	555,588	184,067,045	627,252

Related_Party_Transactions_Sch

Related Party Transactions - Schedule of Siemens Deposits Paid and Certain Development Cost Incurred (Detail) (South Kent Wind LP [Member], CAD)	1 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2013
Related Party Transaction [Line Items]	'	'
Non-cash contribution	79,950,417	80,101,260
Siemens deposit [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	59,000,000	'
Development costs [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	20,950,417	'
Samsung Renewable Energy Inc. [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	29,500,000	'
Samsung Renewable Energy Inc. [Member] | Siemens deposit [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	29,500,000	'
PRHC [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	50,450,417	'
PRHC [Member] | Siemens deposit [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	29,500,000	'
PRHC [Member] | Development costs [Member]	'	'
Related Party Transaction [Line Items]	'	'
Non-cash contribution	20,950,417	'

Related_Party_Transactions_Sch1

Related Party Transactions - Schedule of Balances and Transactions with Related Parties (Detail) (South Kent Wind LP [Member], CAD)	Dec. 31, 2013	Dec. 31, 2012
South Kent Wind LP [Member]	'	'
Related Party Transaction [Line Items]	'	'
Related party payable	42,811,950	'
Deferred development costs transferred	79,450,417	'