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Line of Credit, Maximum Borrowing Capacity, Increase

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

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Description of minimum financial levels (for example, tangible net worth and working capital) and achievement of certain financial ratios (for example, working capital ratio and debt service coverage ratio), and adherence to certain clauses which generally require or restrict certain actions (for example, entering into a debt arrangement with equal or greater seniority, and selling or discontinuing a certain business segment or material subsidiary) to be in compliance with the covenant clauses of the debt agreement. May also include a discussion of the adverse consequences that would result if the entity violates or fails to satisfy the covenants.

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The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

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No definition available.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Amount of the required periodic payments applied to principal.

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Amount, after accumulated amortization, of debt discount.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
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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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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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Description of the conditions for borrowing under the credit facility including the nature of any restrictions.

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

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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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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 the required periodic payment applied to principal.

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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 45
-Paragraph 15
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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Long-Term Debt (Details) - USD ($) $ in Millions			4 Months Ended	6 Months Ended	15 Months Ended	20 Months Ended
Long-Term Debt (Details) - USD ($) $ in Millions	Jul. 21, 2016	Dec. 03, 2014	Jul. 21, 2016	Jan. 31, 2018	Mar. 14, 2016	Jul. 21, 2016	Jul. 31, 2017	Jan. 31, 2017	Mar. 15, 2016
Line of Credit Facility [Line Items]
Maturity date			Mar. 15, 2021
Minimum Liquidity				$ 906.6
Scenario 1
Line of Credit Facility [Line Items]
Line of Credit Facility, Covenant Terms 1				325.00%
Note Agreement, Covenant Terms				325.00%
Scenario 2
Line of Credit Facility [Line Items]
Line of Credit Facility, Covenant Terms 1				350.00%
Note Agreement, Covenant Terms				350.00%
Scenario 3
Line of Credit Facility [Line Items]
Long-term Debt				50
Scenario 4
Line of Credit Facility [Line Items]
Long-term Debt				75
Credit Agreement \| Term Loan Facility
Line of Credit Facility [Line Items]
Maturity date			Dec. 03, 2019
Note Purchase Agreement
Line of Credit Facility [Line Items]
Debt issuance cost						$ 3.4
Debt issuance fees	$ 2.0		$ 2.0			2.0
Reduction of long term debt	1.4		$ 1.4			1.4
Note Purchase Agreement \| Senior Notes
Line of Credit Facility [Line Items]
Debt instrument principal amount		$ 400.0
Note Purchase Agreement \| Senior Notes, Series A
Line of Credit Facility [Line Items]
Maturity date				Dec. 03, 2024
Debt instrument principal amount		$ 100.0
Debt instrument, interest rate		4.07%
Note Purchase Agreement \| Senior Notes, Series B
Line of Credit Facility [Line Items]
Maturity date				Dec. 03, 2026
Debt instrument principal amount		$ 100.0
Debt instrument, interest rate		4.19%
Note Purchase Agreement \| Senior Notes, Series C
Line of Credit Facility [Line Items]
Maturity date				Dec. 03, 2027
Debt instrument principal amount		$ 100.0
Debt instrument, interest rate		4.25%
Note Purchase Agreement \| Senior Notes, Series D
Line of Credit Facility [Line Items]
Maturity date				Dec. 03, 2029
Debt instrument principal amount		$ 100.0
Debt instrument, interest rate		4.35%
Wells Fargo and Bank of America, N.A. \| Line of Credit
Line of Credit Facility [Line Items]
Repayments of Lines of Credit	242.5
Wells Fargo and Bank of America, N.A. \| Revolving Credit Facility \| Line of Credit \| Minimum
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage			0.15%
Wells Fargo and Bank of America, N.A. \| Revolving Credit Facility \| Line of Credit \| Maximum
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage			0.30%
Wells Fargo and Bank of America, N.A. \| Term Loan Facility \| Line of Credit
Line of Credit Facility [Line Items]
Quarterly amortization for term loan			$ 7.5
Wells Fargo and Bank of America, N.A. \| Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 300.0
Wells Fargo and Bank of America, N.A. \| Credit Agreement \| Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity		$ 300.0
Wells Fargo and Bank of America, N.A. \| Credit Agreement \| Term Loan Facility \| Line of Credit
Line of Credit Facility [Line Items]
Quarterly amortization for term loan					$ 18.8
Wells Fargo and Bank of America, N.A. \| First Amendment To Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity									$ 350.0
Line of Credit, Maximum Borrowing Capacity, Increase									50.0
Wells Fargo and Bank of America, N.A. \| First Amendment To Credit Agreement \| Term Loan Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity									93.8
Outstanding borrowings									$ 93.8
Wells Fargo and Bank of America, N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR One \| Minimum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate			0.125%
Wells Fargo and Bank of America, N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR One \| Maximum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate			1.00%
Wells Fargo and Bank of America, N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR Two \| Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate			1.125%
Wells Fargo and Bank of America, N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR Two \| Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate			2.00%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A.
Line of Credit Facility [Line Items]
Maturity date				Jul. 21, 2021
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage				0.125%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Line of Credit Facility, Commitment Fee Percentage				0.20%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Revolving Credit Facility \| Line of Credit
Line of Credit Facility [Line Items]
Outstanding borrowings							$ 231.0
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Scenario 3
Line of Credit Facility [Line Items]
Line of Credit Facility, Covenant Terms				50.0
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Scenario 4
Line of Credit Facility [Line Items]
Line of Credit Facility, Covenant Terms				75.0
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding borrowings				$ 110.7
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Credit Agreement \| Term Loan Facility
Line of Credit Facility [Line Items]
LIBOR variable interest rate				LIBOR rate of 1.56% plus an applicable margin of 1.00%.
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Second Amendment To Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 500.0		$ 500.0			$ 500.0		$ 850.0
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| Federal Funds Effective Swap Rate \| Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				0.50%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| London Interbank Offered Rate (LIBOR) \| Credit Agreement \| Revolving Credit Facility
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				1.00%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR One \| Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				0.00%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR One \| Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				0.75%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR Two \| Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				1.00%
WellsFargo,NationalAssociation,SunTrustBankandBankofAmerica,N.A. \| London Interbank Offered Rate (LIBOR), Adjusted LIBOR Two \| Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Applicable interest rate added to reference rate in order to compute variable interest rate				1.75%