Long-term Debt and Fair Value Disclosure	9 Months Ended
Long-term Debt and Fair Value Disclosure	Jan. 31, 2018
Long-Term Debt and Fair Value Disclosure [Abstract]
Long-term Debt and Fair Value Disclosure	Long-Term Debt and Fair Value Disclosure On June 13, 2017, the Company issued $150 million aggregate principal amount of 3.51% Senior Notes due June 13, 2025, and on August 22, 2017, the Company issued $250 million aggregate principal amount of 3.77% Senior Notes due August 22, 2028. The fair value of the Company’s long-term debt is estimated based on the current rates offered to the Company for debt of the same or similar issues. The fair value of the Company’s long-term debt was approximately $1,320,000 and $941,000 at January 31, 2018 and April 30, 2017, respectively. The Company has an aggregate $100,000 line of credit with $0 outstanding at January 31, 2018 and $900 outstanding at April 30, 2017.

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.