Debt Covenant, Minimum Debt Service Reserves Required

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- Definition

Debt Instrument, Number Of Lenders

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- Definition

Debt Proceeds Used For Debt Service Reserves And Issuance Costs

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No definition available.

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- Definition

Debt Used To Fund Remaining System Purchases

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No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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- Definition

The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Outstanding Loans and Security Agreements - Non-recourse Debt Facilities (Additional Information) (Details)	1 Months Ended			9 Months Ended	12 Months Ended
	Jun. 30, 2018	Sep. 30, 2013 USD ($)	Mar. 31, 2013 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Feb. 28, 2017 USD ($)	Jun. 30, 2015 USD ($) lender	Jul. 31, 2014 USD ($)	Dec. 31, 2012 USD ($)
Debt Instrument [Line Items]
Unused borrowing capacity				$ 1,504,000	$ 1,784,000
Long-term Debt, Gross				792,713,000	1,008,104,000
PPA Company II
Debt Instrument [Line Items]
Repayments of debt				$ 62,188,000	$ 53,726,000
PPA Company II \| Senior secured notes \| Senior Secured Notes due March 2025, Non-Recourse
Debt Instrument [Line Items]
Interest rate percentage			5.22%	5.22%	5.20%
Total amount of loan proceeds			$ 144,800,000
Repayments of debt			28,800,000
Debt proceeds used for debt service reserves and issuance costs			21,700,000
Debt used to fund remaining system purchases			$ 94,300,000
Debt minimum debt service reserves required				$ 11,200,000	$ 11,300,000
Long-term Debt, Gross				82,624,000	91,086,000
PPA Company IIIa
Debt Instrument [Line Items]
Repayments of debt				$ 4,031,000	$ 3,041,000
PPA Company IIIa \| Term loan \| Term Loan due September 2028, Non-Recourse
Debt Instrument [Line Items]
Interest rate percentage				7.50%	7.50%				7.50%
Debt minimum debt service reserves required				$ 3,700,000	$ 3,700,000
Debt face amount									$ 46,800,000
Long-term Debt, Gross				40,937,000	41,927,000
PPA Company IIIb
Debt Instrument [Line Items]
Repayments of debt				3,742,000	3,077,000
PPA Company IIIb \| Term loan \| Term Loan due October 2020, Non-Recourse
Debt Instrument [Line Items]
Debt minimum debt service reserves required				1,700,000	1,700,000
Debt face amount		$ 32,500,000
Long-term Debt, Gross				24,934,000	25,599,000
PPA Company IIIb \| Term loan \| Term Loan due October 2020, Non-Recourse \| LIBOR
Debt Instrument [Line Items]
LIBOR margin (as a percentage)		5.20%
PPA Company IV
Debt Instrument [Line Items]
Repayments of debt				$ 15,007,000	$ 13,697,000
PPA Company IV \| Senior secured notes \| Senior Secured Notes due March 2030, Non-Recourse
Debt Instrument [Line Items]
Interest rate percentage				6.07%	6.10%			6.07%
Debt minimum debt service reserves required				$ 7,400,000	$ 7,000,000
Debt face amount								$ 99,000,000
Long-term Debt, Gross				83,993,000	85,303,000
PPA Company V
Debt Instrument [Line Items]
Repayments of debt				5,148,000	2,834,000
PPA Company V \| Term loan \| Term Loan due December 2021, Non-Recourse
Debt Instrument [Line Items]
Debt face amount							$ 131,200,000
Number of lenders \| lender							5
Commitment fee percentage	0.50%
Long-term Debt, Gross				126,088,000	128,403,000
PPA Company V \| Term loan \| Term Loan due December 2021, Years One Through Three, Non-Recourse \| LIBOR
Debt Instrument [Line Items]
LIBOR margin (as a percentage)	2.25%
PPA Company V \| Term loan \| Term Loan due December 2021, After Year Three, Non-Recourse \| LIBOR
Debt Instrument [Line Items]
LIBOR margin (as a percentage)	2.50%
Letters of Credit
Debt Instrument [Line Items]
Unused borrowing capacity				1,504,000	1,784,000
Letters of Credit \| PPA Company V
Debt Instrument [Line Items]
Maximum borrowing capacity						$ 6,200,000	$ 6,400,000
Amount outstanding				4,700,000	4,400,000
Unused borrowing capacity				$ 1,504,000	$ 1,784,000