Line of credit facility extended maturity date.

No definition available.

Name:	hifr_LineOfCreditFacilityExtendedMaturityDate
Namespace Prefix:	hifr_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

+ Details

Name:	us-gaap_LineOfCreditFacilityExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The effective interest rate at the end of the reporting period.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateAtPeriodEnd
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Description of the interest rate for the amounts borrowed under the credit facility, including the terms and the method for determining the interest rate (for example, fixed or variable, LIBOR plus a percentage, increasing rate, timing of interest rate resets, remarketing provisions).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityInterestRateDescription
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LineOfCreditFacilityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- 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.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=hifr_SharylandDistributionAndTransmissionServicesLimitedLiabilityCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=hifr_NewRevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Borrowings Under Credit Facilities - Additional Information (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Dec. 10, 2014	Jan. 03, 2014	Jun. 28, 2013
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement	$ 0us-gaap_LineOfCredit	$ 57,000,000us-gaap_LineOfCredit
Line of credit facility, remaining borrowing capacity	75,000,000	18,000,000
Revolving credit facility, interest rate description	a rate equal to (i) the one, two, three or six month London Interbank Offered Rate (LIBOR) plus 2.5%, or (ii) a base rate (equal to the highest of (A) the Federal Funds Rate plus ½ of 1%, (B) the Bank of America prime rate and (C) LIBOR plus 1%) plus 1.5%. Letters of credit are subject to a letter of credit fee equal to the daily amount available to be drawn times 2.5%.
Interest rate on credit facility		2.66%
SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement	0	162,000,000
Revolving credit facility, interest rate description	a rate equal to either (1) a base rate, determined as the greatest of (A) the administrative agent’s prime rate, (B) the federal funds effective rate plus ½ of 1% and (C) LIBOR plus 1.00% per annum, plus a margin of either 0.75% or 1.00% per annum, depending on the total debt to capitalization ratio of SDTS on a consolidated basis or (2) LIBOR plus a margin of either 1.75% or 2.00% per annum
Interest rate on credit facility		1.91%
Credit facility, maximum borrowing capacity	250,000,000
SDTS Credit Agreements \| Swingline Loans
Line Of Credit Facility [Line Items]
Line of credit facility, remaining borrowing capacity			5,000,000
Revolving Credit Facility
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement				130,000,000
Credit facility, maturity date	Mar. 31, 2015
Revolving Credit Facility \| SDTS Credit Agreements
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement					75,000,000
Credit facility, maturity date	Jun. 28, 2018
Line of credit facility, remaining borrowing capacity		88,000,000	25,000,000
Credit facility, maximum borrowing capacity			250,000,000
Credit facility, extended maturity date	Dec. 10, 2019
New Revolving Credit Facility
Line Of Credit Facility [Line Items]
Amount of revolving credit facility under agreement			75,000,000
Credit facility, maturity date	Dec. 10, 2019
Line of credit facility, remaining borrowing capacity			$ 15,000,000