Long-term Debt and Finance Lease Obligations, Lines of Credit, and Fair Value Disclosure	9 Months Ended
	Jan. 31, 2021
Long-Term Debt and Fair Value Disclosure [Abstract]
Long-term Debt and Finance Lease Obligations, Lines of Credit, and Fair Value Disclosure	Long-Term Debt and Finance Lease Obligations, Lines of Credit, and Fair Value Disclosure The fair value of the Company’s long-term debt (including current maturities) is estimated based on the current rates offered to the Company for debt of the same or similar issuances. The fair value of the Company’s long-term debt was approximately $1,417,000 and $1,341,000 at January 31, 2021 and April 30, 2020, respectively. Senior Notes On June 30, 2020, the Company entered into a note purchase agreement with respect to the issuance of $650,000 aggregate principal amount of senior notes, consisting of: (i) $325,000 aggregate principal amount of 2.85% Senior Notes, Series G (the “Series G Notes”); and (ii) $325,000 aggregate principal amount of 2.96% Senior Notes, Series H (the “Series H Notes”) (collectively, the “Notes”). The Notes were issued on August 7, 2020. The Series G Notes bear interest at the rate of 2.85% per annum, payable semi-annually on February 7 and August 7 of each year, and mature on August 7, 2030. The Series H Notes bear interest at the rate of 2.96% per annum, payable semi-annually on February 7 and August 7 of each year, and mature on August 6, 2032. The Company used a portion of the proceeds of the Notes to pay off the $569,000 5.22% senior notes that matured on August 9, 2020. Bridge Loan On November 8, 2020, the Company entered into a commitment letter (“Commitment Letter”) with Goldman Sachs Bank USA (“Goldman”), pursuant to which Goldman committed to lend the Company up to $100 million under a new senior unsecured 364-day bridge loan facility (the “Bridge Loan”). As a result of, and concurrent with the effectiveness of the second amendment of the Credit Agreement discussed below, the commitments under the Commitment Letter were reduced, and are now expired, in accordance with the terms thereof. Credit Agreement On December 23, 2020 (the “Amendment Effective Date”), the Company entered into a second amendment (“the Amendment”) to its existing credit agreement dated January 11, 2019, as amended June 30, 2020 (“the Existing Credit Agreement”, together with the Amendment, the “Credit Agreement”) to: (a) increase the revolving commitments thereunder to an aggregate principal amount of $450 million (the “Revolving Facility Increase”, and together with the existing revolving commitments the “Revolving Facility”); and (b) provide for a senior unsecured delayed-draw term loan facility in an aggregate principal amount of up to $300 million (the “Term Loan Facility”). Revolving Facility Increase: The Amendment increased the total borrowing capacity under the Revolving Facility by an aggregate principal amount of $150 million, from $300 million to $450 million. The maturity date of the Revolving Facility remains unchanged, at January 11, 2024. Amounts borrowed under the Revolving Facility bear interest at variable rates based upon, at the Company’s option, either: (a) the LIBO Rate adjusted for statutory reserve requirements (but no less than 0.75%) (the “Adjusted LIBO Rate”), plus a margin ranging from 1.05% to 1.85%; or (b) an alternate base rate, which is the higher of (i) the prime rate announced by the Administrative Agent, (ii) the federal funds rate plus 1/2 of 1.00%, and (iii) the one-month LIBO Rate plus 1.00% (as applicable, the “ABR Rate”), plus a margin ranging from 0.05% to 0.85%. The Revolving Facility also carries a facility fee of 0.20% to 0.40% per annum. The applicable margins and facility fee are dependent upon the Company’s Consolidated Leverage Ratio, as calculated quarterly in accordance with the Credit Agreement (the “Consolidated Leverage Ratio”). The Company had $0 outstanding on the Revolving Facility at January 31, 2021 and $120,000 outstanding at April 30, 2020. Term Loan Facility: The Amendment also provides for a new senior unsecured delayed-draw term loan facility in an aggregate principal amount of up to $300 million, which may be drawn in a single borrowing for up to three months from the Amendment Effective Date. The Term Loan Facility has a maturity date of January 6, 2026 (the “Term Loan Maturity Date”) and its proceeds may be used to finance the pending Buchanan Energy Acquisition (see fn. 9, below) and for working capital needs, capital expenditures, share repurchases and general corporate purposes. Amounts borrowed under the Term Loan Facility will bear interest at variable rates based upon, at the Company’s option, either: (i) the Adjusted LIBO Rate, plus a margin ranging from 1.55% to 2.60%; or (ii) the ABR Rate, plus a margin ranging from 0.20% to 1.60%. The Term Loan Facility also carries a facility fee of 0.20% to 0.40% per annum. The applicable margins and facility fee are dependent upon the Consolidated Leverage Ratio. The outstanding principal balance of the loan drawn on the Term Loan Facility is required to be repaid in equal quarterly installments in an amount equal to 1.25% of the original principal amount, on the last day of each March, June, September and December following the Effective Date, commencing on March 31, 2021, with the balance due on the Term Loan Maturity Date. As of January 31, 2021, the Company has not yet drawn on the Term Loan Facility.

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.