Debt (Details) - USD ($) $ in Thousands	Apr. 30, 2019	Jan. 31, 2019	Jan. 31, 2017
Debt Instrument
Other Long-term Debt	$ 10,511	$ 15,817
Debt and Capital Lease Obligations	1,421,035	1,410,922
Less-current maturities (included as Revolving credit loans and current portion of long-term debt, net)	(123,092)	(110,368)
Long-term Debt and Capital Lease Obligations	1,297,943	1,300,554
Senior Notes
Debt Instrument
Unamortized debt discount and debt issuance costs	(6,788)	(7,166)
Senior Notes, net	993,212	992,834
Senior Notes \| 3.70% Senior Notes
Debt Instrument
Debt Instrument, Face Amount	500,000	500,000	$ 500,000
Senior Notes \| 4.95% Senior Notes
Debt Instrument
Debt Instrument, Face Amount	500,000	500,000	$ 500,000
Term Loan
Debt Instrument
Loans Payable	300,000	300,000
Other Committed And Uncommitted Revolving Credit Facilities
Debt Instrument
Revolving Credit Loan	117,312	102,271
Fair Value, Inputs, Level 1 \| Senior Notes
Debt Instrument
Debt Instrument, Fair Value Disclosure	$ 1,010,000	$ 988,000

Unamortized debt discount and debt issuance costs

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- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

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Amount of short-term debt and current maturity of long-term debt and capital lease obligations due within one year or the normal operating cycle, if longer.

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- Definition

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

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- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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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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- 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.

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- Definition

Including the current and noncurrent portions, aggregate carrying value as of the balance sheet date of loans payable (with maturities initially due after one year or beyond the operating cycle if longer).

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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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Amount of long-term debt classified as other.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.

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