GMS (GMS) 10-Q 5 Dec 19 2020 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Oct. 31, 2019	Nov. 29, 2019
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Oct. 31, 2019
Entity File Number	001-37784
Entity Registrant Name	GMS INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-2931287
Entity Address, Address Line One	100 Crescent Centre Parkway, Suite 800
Entity Address, City or Town	Tucker
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30084
City Area Code	800
Local Phone Number	392-4619
Title of 12(b) Security	Common Stock
Trading Symbol	GMS
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		42,169,225
Current Fiscal Year End Date	--04-30
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Entity Central Index Key	0001600438
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Current assets:
Cash and cash equivalents	$ 36,269	$ 47,338
Trade accounts and notes receivable, net of allowances of $6,414 and $6,432, respectively	480,321	445,771
Inventories, net	293,465	290,829
Prepaid expenses and other current assets	19,621	18,368
Total current assets	829,676	802,306
Property and equipment, net of accumulated depreciation of $140,608 and $123,583, respectively	292,136	282,349
Operating lease right-of-use assets	107,624
Goodwill	621,916	617,327
Intangible assets, net	401,909	429,313
Deferred income taxes	10,199	4,676
Other assets	17,890	13,583
Total assets	2,281,350	2,149,554
Current liabilities:
Accounts payable	168,768	173,751
Accrued compensation and employee benefits	49,981	62,858
Other accrued expenses and current liabilities	80,034	79,848
Current portion of long-term debt	45,963	42,118
Current portion of operating lease liabilities	31,178
Total current liabilities	375,924	358,575
Non-current liabilities:
Long-term debt, less current portion	1,054,085	1,099,077
Long-term operating lease liabilities	81,896
Deferred income taxes, net	10,382	10,226
Other liabilities	63,024	52,500
Total liabilities	1,585,311	1,520,378
Commitments and contingencies
Stockholders' equity:
Common stock, par value $0.01 per share, 500,000 shares authorized; 42,169 and 40,375 shares issued and outstanding as of October 31, 2019 and April 30, 2019, respectively	422	404
Preferred stock, par value $0.01 per share, 50,000 shares authorized; 0 shares issued and outstanding as of October 31, 2019 and April 30, 2019
Exchangeable shares		29,639
Additional paid-in capital	520,855	480,113
Retained earnings	199,552	145,594
Accumulated other comprehensive loss	(24,790)	(26,574)
Total stockholders' equity	696,039	629,176
Total liabilities and stockholders' equity	$ 2,281,350	$ 2,149,554

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Condensed Consolidated Balance Sheets
Trade accounts and notes receivable, allowances (in dollars)	$ 6,414	$ 6,432
Property and equipment, accumulated depreciation (in dollars)	$ 140,608	$ 123,583
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000	500,000
Common stock, shares issued	42,169	40,375
Common stock, shares outstanding	42,169	40,375
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000	50,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Condensed Consolidated Statements of Operations and Comprehensive Income
Net sales		$ 861,929	$ 833,837	$ 1,709,105	$ 1,611,981
Cost of sales (exclusive of depreciation and amortization shown separately below)		577,436	565,687	1,150,958	1,099,015
Gross profit		284,493	268,150	558,147	512,966
Operating expenses:
Selling, general and administrative		200,457	185,268	395,088	370,703
Depreciation and amortization		29,518	30,787	58,793	57,109
Total operating expenses		229,975	216,055	453,881	427,812
Operating income		54,518	52,095	104,266	85,154
Other (expense) income:
Interest expense		(17,559)	(19,182)	(35,836)	(35,370)
Change in fair value of financial instruments			(376)		(6,395)
Write-off of debt discount and deferred financing fees		(707)		(707)
Other income, net		813	434	1,752	1,068
Total other expense, net		(17,453)	(19,124)	(34,791)	(40,697)
Income before taxes		37,065	32,971	69,475	44,457
Provision for income taxes		7,927	8,059	15,517	10,895
Net income		$ 29,138	$ 24,912	$ 53,958	$ 33,562
Weighted average common shares outstanding:
Basic (in shares)		41,761	41,149	41,382	41,121
Diluted (in shares)		42,635	41,918	42,126	41,996
Net income per common share:
Basic (in dollars per share)	[1]	$ 0.70	$ 0.59	$ 1.30	$ 0.80
Diluted (in dollars per share)	[1]	$ 0.68	$ 0.58	$ 1.27	$ 0.78
Comprehensive income
Net income		$ 29,138	$ 24,912	$ 53,958	$ 33,562
Foreign currency translation income (loss)		(409)	(4,902)	11,451	(8,693)
Changes in other comprehensive income, net of tax		(3,602)	378	(9,667)	490
Comprehensive income		$ 25,127	$ 20,388	$ 55,742	$ 25,359
[1]	See Note 15 for detailed calculations

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Exchangeable Shares	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
Balance at Apr. 30, 2018	$ 411		$ 489,007	$ 89,592	$ 441	$ 579,451
Balance (in shares) at Apr. 30, 2018	41,069
Increase (Decrease) in Stockholders' Equity
Net income				33,562		33,562
Issuance of Exchangeable Shares (in shares)		$ 33,194				33,194
Foreign currency translation adjustments					(8,693)	(8,693)
Change in other comprehensive income (loss), net of tax					490	490
Equity-based compensation			1,407			1,407
Tax withholding related to net share settlements of equity awards			(7)			(7)
Exercise of stock options	$ 1		972			973
Exercise of stock options (in shares)	53
Issuance of common stock pursuant to employee stock purchase plan			881			881
Issuance of common stock pursuant to employee stock purchase plan (in shares)	35
Balance at Oct. 31, 2018	$ 412	33,194	492,260	123,154	(7,762)	641,258
Balance (in shares) at Oct. 31, 2018	41,157
Balance at Apr. 30, 2019	$ 404	29,639	480,113	145,594	(26,574)	$ 629,176
Balance (in shares) at Apr. 30, 2019	40,375					40,375
Increase (Decrease) in Stockholders' Equity
Net income				53,958		$ 53,958
Exercise of Exchangeable Shares	$ 11	$ (29,639)	29,628
Exercise of Exchangeable Shares (in shares)	1,129
Foreign currency translation adjustments					11,451	11,451
Change in other comprehensive income (loss), net of tax					(9,667)	(9,667)
Equity-based compensation			3,620			3,620
Tax withholding related to net share settlements of equity awards			(282)			(282)
Exercise of stock options	$ 5		6,756			6,761
Exercise of stock options (in shares)	534
Vesting of restricted stock units	$ 1		(1)
Vesting of restricted stock units (in shares)	55
Issuance of common stock pursuant to employee stock purchase plan	$ 1		1,021			1,022
Issuance of common stock pursuant to employee stock purchase plan (in shares)	76
Balance at Oct. 31, 2019	$ 422		$ 520,855	$ 199,552	$ (24,790)	$ 696,039
Balance (in shares) at Oct. 31, 2019	42,169					42,169

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Cash flows from operating activities:
Net income	$ 53,958	$ 33,562
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,793	57,109
Write-off and amortization of debt discount and debt issuance costs	2,368	1,665
Provision for losses on accounts and notes receivable	375	81
Provision for obsolescence of inventory	195	229
Effects of fair value adjustments to inventory	151	4,129
Increase in fair value of contingent consideration	380	460
Equity-based compensation	5,591	3,204
Gain on sale and disposal of assets	(742)	(294)
Change in fair value of financial instruments		6,395
Deferred income taxes	(2,380)	(5,145)
Changes in assets and liabilities net of effects of acquisitions:
Trade accounts and notes receivable	(29,932)	(45,355)
Inventories	1,800	(4,553)
Prepaid expenses and other assets	1,573	(343)
Accounts payable	(5,486)	9,516
Accrued compensation and employee benefits	(12,974)	(9,550)
Derivative liability		(10,778)
Other accrued expenses and liabilities	(3,743)	5,325
Cash provided by operating activities	69,927	45,657
Cash flows from investing activities:
Purchases of property and equipment	(14,637)	(9,156)
Proceeds from sale of assets	1,056	638
Acquisition of businesses, net of cash acquired	(10,633)	(578,917)
Cash used in investing activities	(24,214)	(587,435)
Cash flows from financing activities:
Repayments on the revolving credit facility	(558,906)	(469,647)
Borrowings from the revolving credit facility	562,698	623,117
Payments of principal on long-term debt	(54,984)	(4,984)
Payments of principal on finance lease obligations	(12,310)	(8,820)
Borrowings from term loan amendment		996,840
Repayments from term loan amendment		(571,840)
Debt issuance costs	(1,286)	(7,933)
Proceeds from exercises of stock options	6,761	973
Other financing activities	1,022	873
Cash (used in) provided by financing activities	(57,005)	558,579
Effect of exchange rates on cash and cash equivalents	223	(360)
(Decrease) increase in cash and cash equivalents	(11,069)	16,441
Cash and cash equivalents, beginning of period	47,338	36,437
Cash and cash equivalents, end of period	36,269	52,878
Supplemental cash flow disclosures:
Cash paid for income taxes	25,642	10,469
Cash paid for interest	$ 33,654	$ 30,966

Business, Basis of Presentation

Business, Basis of Presentation and Summary of Significant Accounting Policies	6 Months Ended
	Oct. 31, 2019
Business, Basis of Presentation and Summary of Significant Accounting Policies
Business, Basis of Presentation and Summary of Significant Accounting Policies	1. Business, Basis of Presentation and Summary of Significant Accounting Policies ​ Business ​ Founded in 1971, GMS Inc. (“we,” “our,” “us,” or the “Company”), through its wholly-owned operating subsidiaries, is a distributor of specialty building products including wallboard, suspended ceilings systems, or ceilings, steel framing and other complementary building products. We purchase products from a large number of manufacturers and then distribute these goods to a customer base consisting of wallboard and ceilings contractors and homebuilders and, to a lesser extent, general contractors and individuals. We operate a network of more than 250 distribution centers across the United States and Canada. ​ Basis of Presentation ​ The condensed consolidated financial statements included in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) that permit reduced disclosure for interim periods. In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all normal and recurring adjustments necessary for a fair presentation of the results of operations, financial position and cash flows. All adjustments are of a normal recurring nature unless otherwise disclosed. The results of operations for interim periods are not necessarily indicative of results for any other interim period or the entire fiscal year. As a result, the unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements included in our Annual Report on Form 10-K for the fiscal year ended April 30, 2019. ​ Principles of Consolidation ​ The condensed consolidated financial statements present the results of operations, financial position, stockholders’ equity and cash flows of the Company and its subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation. The results of operations of businesses acquired are included from their respective dates of acquisition. ​ Use of Estimates ​ The preparation of financial statements in conformity with Generally Accepted Accounting Principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. ​ Foreign Currency Translation ​ Assets and liabilities of the Company’s Canadian subsidiaries are translated at the exchange rate prevailing at the balance sheet date, while income and expenses are translated at average rates for the period. Translation gains and losses are reported as a separate component of stockholders’ equity and other comprehensive income. Gains and losses on foreign currency transactions are recognized in the Condensed Consolidated Statements of Operations and Comprehensive Income within other income, net. ​ Insurance Liabilities ​ The Company is self-insured for certain losses related to medical claims. The Company has stop-loss coverage to limit the exposure arising from medical claims. In addition, the Company has deductible-based insurance policies for certain losses related to general liability, automobile and workers’ compensation. The deductible amount per incident is $0.3 million, $0.5 million and $1.0 million for general liability, workers’ compensation and automobile, respectively. The coverage consists of a primary layer and an excess layer. The primary layer of coverage is from $0.5 million to $2.0 million and the excess layer cover claims from $2.0 million to $100.0 million. The expected ultimate cost for claims incurred as of the balance sheet date is not discounted and is recognized as a liability. Insurance losses for claims filed and claims incurred but not reported are accrued based upon estimates of the aggregate liability for uninsured claims using loss development factors, actuarial assumptions and historical loss development experience. ​ As of October 31, 2019 and April 30, 2019, the aggregate liabilities for medical self-insurance were $3.9 million and $3.4 million, respectively, and are included in other accrued expenses and current liabilities in the Condensed Consolidated Balance Sheets. As of October 31, 2019 and April 30, 2019, reserves for general liability, automobile and workers’ compensation totaled approximately $23.8 million and $17.7 million, respectively, and are included in other accrued expenses and current liabilities and other liabilities in the Condensed Consolidated Balance Sheets. As of October 31, 2019 and April 30, 2019, expected recoveries for medical self-insurance, general liability, automobile and workers’ compensation totaled approximately $10.3 million and $6.0 million, respectively, and are included in prepaid expenses and other current assets and other assets in the Condensed Consolidated Balance Sheets. ​ Income Taxes ​ The Company considers each interim period an integral part of the annual period and measures tax expense (benefit) using an estimated annual effective income tax rate. Estimates of the annual effective income tax rate at the end of interim periods are, out of necessity, based on evaluation of possible future events and transactions and may be subject to subsequent refinement or revision. The Company forecasts its estimated annual effective income tax rate and then applies that rate to its year-to-date pre-tax ordinary income (loss), subject to certain loss limitation provisions. In addition, certain specific transactions are excluded from the Company’s estimated annual effective tax rate computation, but are discretely recognized within income tax expense (benefit) in their respective interim period. Future changes in the forecasted annual income (loss) projections, tax rate changes, or discrete tax items could result in significant adjustments to quarterly income tax expense (benefit) in future periods. ​ The Company evaluates its deferred tax assets quarterly to determine if valuation allowances are required. In this evaluation, the Company considers both positive and negative evidence in determining whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The primary negative evidence considered includes the cumulative operating losses generated in prior periods. The primary positive evidence considered includes the reversal of deferred tax liabilities primarily related to depreciation and amortization that would occur within the same jurisdiction and during the carryforward period necessary to absorb the federal and state net operating losses and other deferred tax assets. ​ Deferred tax assets and liabilities are computed by applying the federal, provincial and state income tax rates in effect to the gross amounts of temporary differences and other tax attributes, such as net operating loss carry-forwards. In assessing if the deferred tax assets will be realized, the Company considers whether it is more likely than not that some or all of these deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the period in which these deductible temporary differences reverse. ​ Fair Value of Financial Instruments ​ Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Authoritative guidance for fair value measurements establishes a three-level hierarchy that prioritizes the inputs to valuation models based upon the degree to which they are observable. The three levels of the fair value measurement hierarchy are as follows: ​ Level 1 Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. Level 2 Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 Inputs are unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. ​ The carrying values of the Company’s cash, cash equivalents, trade receivables and trade payables approximate their fair values because of their short-term nature. Based on borrowing rates available to the Company for loans with similar terms, the carrying values of the Company’s debt instruments approximate fair value. See Note 11, “Fair Value Measurements,” for additional information with respect to the Company’s fair value measurements. ​ Earnings Per Share ​ Basic earnings per share is computed by dividing net income available to common stockholders by the weighted average number of outstanding shares of common stock for the period. Diluted earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock, including stock options and restricted stock units (collectively “Common Stock Equivalents”), were exercised or converted into common stock. The dilutive effect of outstanding stock options and restricted stock units is reflected in diluted earnings per share by application of the treasury stock method. In applying the treasury stock method for stock-based compensation arrangements, the assumed proceeds are computed as the sum of the amount the employee must pay upon exercise and the amount of compensation cost attributed to future services and not yet recognized. Diluted earnings per share is computed by increasing the weighted-average number of outstanding shares of common stock computed in basic earnings per share to include the dilutive effect of Common Stock Equivalents for the period. In periods of net loss, the number of shares used to calculate diluted loss per share is the same as basic net loss per share. ​ The holders of the Company’s Exchangeable Shares (as defined in Note 8, “Stockholders’ Equity”) were entitled to receive dividends or distributions that are equal to any dividends or distributions on the Company’s common stock. As a result, when the Exchangeable Shares were outstanding, they were classified as a participating security and thereby required the allocation of income that would have otherwise been available to common stockholders when calculating earnings per share. Diluted earnings per share is calculated by utilizing the most dilutive result of the if-converted and two-class methods. In both methods, net income attributable to common stockholders and the weighted-average common shares outstanding are adjusted to account for the impact of the assumed issuance of potential common shares that are dilutive, subject to dilution sequencing rules. ​ Recently Adopted Accounting Pronouncements ​ Leases – ​ On July 30, 2018, the FASB issued new guidance that provided entities with an additional (and optional) transition method to adopt the new lease standard. Under this new transition method, an entity initially applies the new lease standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ​ The Company adopted the new lease standard on May 1, 2019 using the optional transition method. The Company elected the package of practical expedients permitted in the guidance, which among other things, allows the Company to carry forward the historical accounting relating to lease identification and classification for existing leases upon adoption. The Company also elected to use the practical expedient to not separate lease and nonlease components. The Company did not elect the hindsight practical expedient. The Company made an accounting policy election to keep leases with an initial term of 12 months or less off the Consolidated Balance Sheet. ​ The adoption of the standard resulted in the recording of operating lease ROU assets and operating lease liabilities of $118.8 million on the Condensed Consolidated Balance Sheet as of the adoption date. The Company also reclassified deferred rent of $4.8 million from liabilities into its operating lease ROU assets. The adoption did not have a material impact on the Company’s Statement of Operations or Statement of Cash Flows. See Note 6, “Leases,” for information and disclosures regarding leases. ​ Recently Issued Accounting Pronouncements ​ Credit Losses – ​ Goodwill ​ Fair Value Measurement Disclosures – ​

Revenue

Revenue	6 Months Ended
	Oct. 31, 2019
Revenue
Revenue	2. Revenue ​ Revenue Recognition ​ Revenue is recognized upon transfer of control of promised goods to customers at an amount that reflects the consideration the Company expects to receive in exchange for those goods. Revenue is recognized net of any taxes collected from customers, which are subsequently remitted to governmental authorities. The Company includes shipping and handling costs billed to customers in net sales. These costs are recognized as a component of selling, general and administrative expenses when the Company does not bill the customer. ​ See Note 14, “Segments,” for information regarding disaggregation of revenue, including revenue by product and by geographic area. ​ Performance Obligations ​ The Company satisfies its performance obligations at a point in time, which is upon delivery of products. The Company’s payment terms vary by the type and location of its customers. The amount of time between point of sale and when payment is due is not significant and the Company has determined its contracts do not include a significant financing component. ​ Our contracts with customers involve performance obligations that are one year or less. Therefore, we applied the standard’s optional exemption that permits the omission of information about our unfulfilled performance obligations as of the balance sheet dates. ​ Significant Judgements ​ The Company’s contracts may include terms that could cause variability in the transaction price, including customer rebates, returns and cash discounts for early payment. Variable consideration is estimated and included in total consideration based on the expected value method. These estimates are based on historical experience, anticipated performance and other factors known at the time. The Company only includes estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur when the uncertainty associated with the variable consideration is resolved. ​ Contract Balances ​ Receivables from contracts with customers were $454.6 million and $431.4 million as of October 31, 2019 and April 30, 2019, respectively. The Company did not have material amounts of contract assets or liabilities as of October 31, 2019 or April 30, 2019. ​

Business Acquisitions

Business Acquisitions	6 Months Ended
	Oct. 31, 2019
Business Acquisitions
Business Acquisitions	3. Business Acquisitions ​ The Company accounts for business combinations by recognizing the assets acquired and liabilities assumed at the acquisition date fair value. In valuing acquired assets and liabilities, fair value estimates use Level 3 inputs, including future expected cash flows and discount rates. Goodwill is measured as the excess of consideration transferred over the fair values of the assets acquired and the liabilities assumed. While the Company uses its best estimates and assumptions as a part of the purchase price allocation process to accurately value assets acquired and liabilities assumed at the acquisition date, the Company’s estimates are inherently uncertain and subject to refinement. As a result, during the measurement period, which may be up to one year from the acquisition date, the Company records adjustments to the assets acquired and liabilities assumed, with the corresponding offset to goodwill. Upon the conclusion of the measurement period, any subsequent adjustments arising from new facts and circumstances are recorded to the Condensed Consolidated Statements of Operations and Comprehensive Income. The results of operations of acquisitions are reflected in the Company’s Condensed Consolidated Financial Statements from the date of acquisition. ​ On June 3, 2019, the Company acquired the acoustical and drywall operations of J.P. Hart Lumber Company (“Hart Acoustical and Drywall Supply”). Hart Acoustical and Drywall Supply distributes drywall, metal studs, insulation and ceiling tiles through two locations in San Antonio, TX and one location in La Feria, TX. The impact of this acquisition is not material to the Company’s Consolidated Financial Statements. ​

Goodwill and Intangible Assets

Goodwill and Intangible Assets	6 Months Ended
	Oct. 31, 2019
Goodwill and Intangible Assets
Goodwill and Intangible Assets	4. Goodwill and Intangible Assets Goodwill The following table presents changes in the carrying amount of goodwill during the six months ended October 31, 2019: ​ ​ ​ ​ ​ ​ Carrying ​ ​ Amount ​ ​ (in thousands) Balance as of April 30, 2019 ​ $ 617,327 Goodwill acquired ​ ​ 877 Translation adjustment ​ 3,712 Balance as of October 31, 2019 ​ $ 621,916 ​ Intangible Assets The following tables present the components of the Company’s definite-lived intangible assets as of October 31, 2019 and April 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ Weighted ​ October 31, 2019 ​ ​ Useful ​ Average ​ Gross ​ ​ ​ Net ​ ​ Lives ​ Amortization ​ Carrying ​ Accumulated ​ Carrying ​ (years) Period Amount Amortization Value ​ ​ (dollars in thousands) Customer relationships ​ 5 - 16 ​ 12.8 ​ $ 527,556 ​ $ 245,252 ​ $ 282,304 Definite-lived tradenames ​ 5 - 20 ​ 16.3 ​ 56,637 ​ 8,843 ​ 47,794 Vendor agreements ​ 8 - 10 ​ 8.3 ​ 6,644 ​ 4,164 ​ 2,480 Developed technology ​ 5 ​ 4.9 ​ ​ 5,318 ​ ​ 1,532 ​ ​ 3,786 Leasehold interests ​ 1 - 15 ​ 7.6 ​ 3,724 ​ 1,875 ​ 1,849 Other ​ 3 - 5 ​ 3.4 ​ ​ 4,175 ​ ​ 1,846 ​ ​ 2,329 Totals ​ ​ ​ ​ ​ $ 604,054 ​ $ 263,512 ​ $ 340,542 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ Weighted ​ April 30, 2019 ​ ​ Useful ​ Average ​ Gross ​ ​ ​ Net ​ ​ Lives Amortization Carrying Accumulated Carrying ​ (years) Period Amount Amortization Value ​ ​ (dollars in thousands) Customer relationships ​ 5 - 16 ​ 12.8 ​ $ 520,703 ​ $ 214,044 ​ $ 306,659 Definite-lived tradenames ​ 5 - 20 ​ 16.3 ​ 56,018 ​ 6,993 ​ 49,025 Vendor agreements ​ 8 - 10 ​ 8.3 ​ 6,644 ​ 3,761 ​ 2,883 Developed technology ​ 5 ​ 4.9 ​ ​ 5,209 ​ ​ 971 ​ ​ 4,238 Leasehold interests ​ 1 - 15 ​ 7.6 ​ 3,707 ​ 1,502 ​ 2,205 Other ​ 3 - 5 ​ 3.4 ​ ​ 4,118 ​ ​ 1,182 ​ ​ 2,936 Totals ​ ​ ​ ​ ​ $ 596,399 ​ $ 228,453 ​ $ 367,946 ​ Definite-lived intangible assets are amortized over their estimated useful lives. The Company amortizes its customer relationships using an accelerated method to match the estimated cash flows generated by such assets, and amortizes its other definite-lived intangibles using the straight-line method because a pattern to which the expected benefits will be consumed or otherwise used up could not be reliably determined. Amortization expense related to definite-lived intangible assets was $16.9 million and $19.2 million for the three months ended October 31, 2019 and 2018, respectively, and $33.8 million and $35.0 million for the six months ended October 31, 2019 and 2018, respectively. Amortization expense is recorded in depreciation and amortization expense in the Condensed Consolidated Statements of Operations and Comprehensive Income. Based on the current amount of definite-lived intangible assets, the Company expects to record amortization expense of approximately $31.5 million during the remaining six months in the fiscal year ending April 30, 2020 and $55.4 million, $46.4 million, $38.7 million, $31.5 million and $137.0 million during the fiscal years ending April 30, 2021, 2022, 2023, 2024 and thereafter, respectively. Actual amortization expense to be reported in future periods could differ materially from these estimates as a result of acquisitions, changes in useful lives, foreign currency exchange rate fluctuations and other relevant factors. The Company’s indefinite-lived intangible assets consist of tradenames that had a carrying amount of $61.4 million as of October 31, 2019 and April 30, 2019.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Oct. 31, 2019
Long-Term Debt
Long-Term Debt	5. Long-Term Debt The Company’s long-term debt consisted of the following as of October 31, 2019 and April 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ 2019 2019 ​ ​ (in thousands) First Lien Facility (1) (2) ​ $ 919,564 ​ $ 972,650 ABL Facility ​ 47,776 ​ 43,972 Finance lease obligations ​ 116,510 ​ 109,286 Installment notes at fixed rates up to 5.0%, due in monthly and annual installments through 2024 (3) ​ 16,198 ​ 15,287 Carrying value of debt ​ 1,100,048 ​ 1,141,195 Less current portion ​ 45,963 ​ 42,118 Long-term debt ​ $ 1,054,085 ​ $ 1,099,077 (1) Net of unamortized discount of $1,862 and $2,149 as of October 31, 2019 and April 30, 2019, respectively. (2) Net of deferred financing costs of $10,460 and $12,072 as of October 31, 2019 and April 30, 2019, respectively. (3) Net of unamortized discount of $1,276 and $1,200 as of October 31, 2019 and April 30, 2019, respectively. First Lien Facility The Company has a senior secured first lien term loan facility (the "First Lien Facility") with aggregate principal amount of $919.6 million outstanding as of October 31, 2019. The First Lien Facility is due in June 2025 and the Company is required to make quarterly principal payments of 0.25% of the aggregate principal amount. The First Lien Facility bears interest at a floating rate based on LIBOR plus 2.75%, with a 0% floor. As of October 31, 2019, the applicable rate of interest was 4.54%. On September 30, 2019, the Company made a $50.0 million prepayment of outstanding principal amount of its First Lien Facility. The Company recorded a write-off of debt discount and deferred financing fees of $0.7 million, which is included in write-off of discount and deferred financing fees in the Condensed Consolidated Statements of Operations and Comprehensive Income. Asset Based Lending Facility The Company has an asset based revolving credit facility (the “ABL Facility”) that provides for aggregate revolving commitments of $445.0 million (including same day swing line borrowings of $34.5 million). Extensions of credit under the ABL Facility are limited by a borrowing base calculated periodically based on specified percentages of the value of eligible inventory and eligible accounts receivable, subject to certain reserves and other adjustments. On September 30, 2019, the Company amended its ABL Facility to ​ At the Company’s option, the interest rates applicable to the loans under the ABL Facility are based at LIBOR or base rate plus, in each case, an applicable margin. The margins applicable for each elected interest rate are subject to a pricing grid, as defined in the ABL Facility agreement, based on average daily availability for the most recent fiscal quarter. As of October 31, 2019, the applicable rate of interest was 3.91%. The ABL Facility also contains an unused commitment fee subject to utilization, as included in the ABL Facility agreement. During the six months ended October 31, 2019, the Company made net borrowings under the ABL Facility of $3.8 million. As of October 31, 2019, the Company had available borrowing capacity of approximately $387.6 million under the ABL Facility. The ABL Facility will mature on September 30, 2024 unless the individual affected lenders agree to extend the maturity of their respective loans under the ABL Facility upon the Company’s request and without the consent of any other lender. The ABL Facility contains a cross default provision with the First Lien Facility. Covenants under the First Lien Facility and ABL Facility The First Lien Facility contains a number of covenants that limit our ability and the ability of our restricted subsidiaries, as described in the First Lien Credit Agreement, to: incur more indebtedness; pay dividends, redeem or repurchase stock or make other distributions; make investments; create restrictions on the ability of our restricted subsidiaries to pay dividends to us or make other intercompany transfers; create liens securing indebtedness; transfer or sell assets; merge or consolidate; enter into certain transactions with our affiliates; and prepay or amend the terms of certain indebtedness. The Company was in compliance with all restrictive covenants as of October 31, 2019. The ABL Facility contains certain affirmative covenants, including financial and other reporting requirements. The Company was in compliance with all such covenants as of October 31, 2019. Titan Revolving Credit Facility Through its WSB Titan (“Titan”) subsidiary, the Company has a revolving credit facility (the “Titan Facility”) that provides for aggregate revolving commitments of $22.8 million ($30.0 million Canadian dollars). The Titan Facility bears interest at the Canadian prime rate plus a marginal rate based on the level determined by Titan’s total debt to EBITDA ratio at the end of the most recently completed fiscal quarter or year. As of October 31, 2019, the Company had available borrowing capacity of approximately $22.8 million under the Titan Facility. The Titan Facility matures on June 28, 2022. Debt Maturities As of October 31, 2019, the maturities of long-term debt were as follows ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First Lien ​ ​ ABL ​ Finance ​ Installment ​ ​ ​ ​ Facility(1) ​ Facility Leases Notes(2) ​ Total Years ending April 30, ​ (in thousands) 2020 (remaining six months) ​ $ 4,984 ​ $ — ​ $ 14,981 ​ $ 1,133 ​ $ 21,098 2021 ​ 9,968 ​ ​ — ​ ​ 30,761 ​ ​ 4,874 ​ 45,603 2022 ​ 9,968 ​ ​ — ​ ​ 27,560 ​ ​ 4,438 ​ 41,966 2023 ​ 9,968 ​ ​ — ​ ​ 22,001 ​ ​ 4,404 ​ 36,373 2024 ​ 9,968 ​ ​ — ​ ​ 14,895 ​ ​ 1,781 ​ 26,644 Thereafter ​ 887,030 ​ ​ 47,776 ​ ​ 6,312 ​ ​ 844 ​ 941,962 ​ ​ $ 931,886 ​ $ 47,776 ​ $ 116,510 ​ $ 17,474 ​ $ 1,113,646 (1) Gross of unamortized discount of $1,862 and deferred financing costs of $10,460 as of October 31, 2019. (2) Gross of unamortized discount of $1,276 as of October 31, 2019.

Leases

Leases	6 Months Ended
	Oct. 31, 2019
Leases
Leases	6. Leases ​ The Company leases office and warehouse facilities, distribution equipment and its fleet of vehicles. The Company’s leases have lease terms ranging from one to eleven years. The Company’s facility leases generally contain renewal options for periods ranging from one to five years. The exercise of lease renewal options is typically at the Company’s sole discretion. The Company does not recognize ROU assets or lease liabilities for renewal options unless it is determined that the Company is reasonably certain of exercising renewal options at lease inception. Certain of the Company’s equipment leases include options to purchase the leased property and certain of the Company’s equipment leases contain residual value guarantees. Any payment deemed probable is included in the Company’s lease liability. The Company’s lease agreements do not contain any material restrictive covenants. ​ The Company determines if an arrangement is a lease at inception and evaluates whether the lease meets the classification criteria of a finance or operating lease. Operating leases are included in operating lease right-of-use assets, current portion of operating lease liabilities and long-term operating lease liabilities in the Condensed Consolidated Balance Sheet. Finance leases are included in property and equipment, current portion of long-term debt and long-term debt in the Condensed Consolidated Balance Sheet. ​ Lease ROU assets and lease liabilities are recognized at the commencement date based on the present value of the future lease payments over the lease term. For leases that do not provide an implicit rate, the Company uses its incremental borrowing rate in determining the present value of future payments. The Company determines its incremental borrowing rate based on the applicable lease terms and the current economic environment. Lease ROU assets also include any lease payments made in advance and excludes lease incentives and initial direct costs incurred. Some of the Company’s lease agreements contain rent escalation clauses (including index-based escalations), rent holidays, capital improvements funding or other lease concessions. Lease expense is recognized on a straight-line basis based on the fixed component over the lease term. Variable lease costs consist primarily of taxes, insurance and common area or other maintenance costs for leased facilities and vehicles and equipment, which are paid based on actual costs incurred. ​ The components of lease expense were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months ​ Six Months ​ ​ Ended ​ Ended ​ ​ October 31, 2019 ​ October 31, 2019 ​ ​ (in thousands) Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of right-of-use assets ​ $ 6,054 ​ $ 12,113 Interest on lease liabilities ​ ​ 3,367 ​ ​ 6,789 Operating lease cost ​ ​ 10,289 ​ ​ 20,709 Variable lease cost ​ ​ 3,414 ​ ​ 6,613 Total lease cost ​ $ 23,124 ​ $ 46,224 ​ Operating lease cost, including variable lease cost, is included in selling, general and administrative expenses; amortization of finance ROU assets is included in depreciation and amortization; and interest on finance lease liabilities is included in interest expense in the Condensed Consolidated Statement of Operations and Comprehensive Income. Supplemental cash flow information related to leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months ​ ​ ​ ​ ​ Ended ​ ​ ​ ​ ​ October 31, 2019 ​ ​ ​ ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ ​ ​ ​ $ 10,141 Operating cash flows from finance leases ​ ​ ​ ​ ​ 6,789 Financing cash flows from finance leases ​ ​ ​ ​ ​ 12,310 Right-of-use assets obtained in exchange for lease obligations ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 6,569 Finance leases ​ ​ ​ ​ ​ 22,812 ​ Other information related to leases was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, 2019 ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ Finance leases included in property and equipment ​ ​ ​ ​ ​ ​ ​ Property and equipment ​ ​ ​ ​ $ 149,769 ​ Accumulated depreciation ​ ​ ​ ​ ​ (34,513) ​ Property and equipment, net ​ ​ ​ ​ $ 115,256 ​ Weighted-average remaining lease term (years) ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 4.9 ​ Finance leases ​ ​ ​ ​ ​ 3.4 ​ Weighted-average discount rate ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 5.5 % Finance leases ​ ​ ​ ​ ​ 5.4 % ​ Future minimum lease payments under non-cancellable leases as of October 31, 2019 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Finance Operating Year Ended April 30, ​ (in thousands) 2020 (remaining six months) ​ $ 21,178 ​ $ 19,376 2021 ​ 40,387 ​ 32,481 2022 ​ 33,600 ​ 23,918 2023 ​ 24,855 ​ 17,591 2024 ​ 15,753 ​ 13,264 Thereafter ​ 6,471 ​ 23,016 Total lease payments ​ $ 142,244 ​ $ 129,646 Less imputed interest ​ 25,734 ​ 16,572 Total ​ $ 116,510 ​ $ 113,074 ​

Income Taxes

Income Taxes	6 Months Ended
	Oct. 31, 2019
Income Taxes
Income Taxes	7. Income Taxes General. The Company is subject to provisions of the Tax Act related to current tax on global intangible low-taxed income (“GILTI”) earned by certain foreign subsidiaries. The FASB Staff Q&A, Topic 740 No. 5, Accounting for Global Intangible Low-Taxed Income, states that an entity can make an accounting policy election to either recognize deferred taxes for temporary differences expected to reverse as GILTI in future years or provide for the tax expense related to GILTI in the year the tax is incurred. We have elected to recognize the tax on GILTI as a period expense in the period the tax is incurred. ​ Valuation allowance Uncertain tax positions

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Oct. 31, 2019
Stockholders' Equity
Stockholders' Equity	8. Stockholders’ Equity Exchangeable Shares In connection with the acquisition of Titan on June 1, 2018, the Company issued 1.1 million shares of equity that were exchangeable for the Company’s common stock on a one-for-one basis (“Exchangeable Shares”). The Exchangeable Shares were issued by an indirect wholly-owned subsidiary of the Company. The Exchangeable Shares ranked senior to the Company’s common stock with respect to dividend rights and rights on liquidation, dissolution and winding-up. The holders of the Exchangeable Shares were entitled to receive dividends or distributions that were equal to any dividends or distributions on the Company’s common stock. The holders of the Exchangeable Shares did not have voting rights. The Exchangeable Shares contained rights that allowed the holders to exchange their Exchangeable Shares for GMS common stock at any time on a one-for-one basis. If converted, the holders were prevented from transferring such GMS common stock for one year from the Titan acquisition date. On June 13, 2019, the holders of the Exchangeable Shares exchanged all of the Exchangeable Shares for 1.1 million shares of the Company’s common stock. Following such exchange, the Exchangeable Shares ceased to be outstanding. Share Repurchase Program On November 30, 2018, the Company’s Board of Directors authorized a common stock repurchase program to repurchase up to $75.0 million outstanding common stock. The Company may conduct repurchases under the share repurchase program through open market transactions, under trading plans in accordance with SEC Rule 10b5-1 and/or in privately negotiated transactions, in compliance with Rule 10b-18 under the Exchange Act of 1934, as amended, subject to a variety of factors, including, but not limited to, our liquidity, credit availability, general business and market conditions, our debt covenant restrictions and the availability of alternative investment opportunities. The share repurchase program does not obligate us to acquire any particular amount of common stock, and it may be suspended or terminated at any time at the Company’s discretion. The Company did not repurchase any shares of its common stock during the six months ended October 31, 2019. As of October 31, 2019, the Company had $58.5 million of remaining authorization under its repurchase program. Secondary Public Offering ​ On September 9, 2019, AEA Investors LP and its affiliates Accumulated Other Comprehensive Loss The following table sets forth the changes to accumulated other comprehensive loss, net of tax, by component for the six months ended October 31, 2019: ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ Other ​ Comprehensive ​ ​ Loss ​ ​ (in thousands) Accumulated other comprehensive loss as of April 30, 2019 ​ $ (26,574) Foreign currency translation adjustments ​ ​ 11,451 Other comprehensive loss on derivative instruments ​ (9,667) Accumulated other comprehensive loss as of October 31, 2019 ​ $ (24,790) ​ Other comprehensive loss on derivative instruments for the six months ended October 31, 2019 is net of $3.0 million of tax.

Equity-Based Compensation

Equity-Based Compensation	6 Months Ended
	Oct. 31, 2019
Equity-Based Compensation
Equity-Based Compensation	9. Equity-Based Compensation General The Company measures compensation cost for all share-based awards at fair value on the grant date (or measurement date if different) and recognizes compensation expense, net of estimated forfeitures, over the requisite service period for awards expected to vest. The Company estimates the fair value of stock options using the Black-Scholes valuation model, and determines the fair value of restricted stock units based on the quoted price of GMS’s common stock on the date of grant . Equity-based compensation expense related to stock options and restricted stock units was $3.4 million and $1.3 million during the six months ended October 31, 2019 and 2018, respectively, and is included in selling, general and administrative expenses in the Condensed Consolidated Statements of Operations and Comprehensive Income. Stock Option Awards The following table presents stock option activity for the six months ended October 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ Number of ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Options ​ Price ​ Life (years) ​ Value ​ ​ (shares and dollars in thousands) Outstanding as of April 30, 2019 2,080 ​ $ 16.34 6.15 $ 7,615 Options granted 380 ​ ​ 21.52 ​ Options exercised (534) ​ 12.65 ​ Options forfeited (102) ​ 25.59 ​ Options expired — ​ — ​ ​ Outstanding as of October 31, 2019 1,824 ​ $ 17.96 6.57 ​ $ 22,326 Exercisable as of October 31, 2019 1,242 ​ $ 15.32 5.35 ​ $ 18,354 Vested and expected to vest as of October 31, 2019 1,816 ​ $ 17.93 6.56 ​ $ 22,272 ​ The aggregate intrinsic value represents the value of the Company’s closing stock price on the last trading day of the period in excess of the weighted average exercise price multiplied by the number of options outstanding, exercisable or expected to vest. Options expected to vest are unvested shares net of expected forfeitures. The total intrinsic value of options exercised during the six months ended October 31, 2019 and 2018 was $8.6 million and $0.7 million, respectively. As of October 31, 2019, there was $4.6 million of total unrecognized compensation cost related to stock options. That cost is expected to be recognized over a weighted-average period of 2.4 years. The fair value of stock options granted during the six months ended October 31, 2019 and 2018 was estimated using the Black-Scholes option-pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ October 31, ​ ​ 2019 ​ 2018 Volatility ​ 49.94 % ​ 33.71 % Expected life (years) ​ 6.0 ​ ​ 6.0 ​ Risk-free interest rate ​ 1.97 % ​ 2.87 % Dividend yield ​ — % ​ — % ​ The weighted average grant date fair value of options granted during the was $10.55 per share and $9.72 per share, respectively. ​ Restricted Stock Units The following table presents restricted stock unit activity for the six months ended October 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of ​ Average ​ ​ Restricted ​ Exercise ​ ​ Stock Units ​ Price ​ ​ (shares in thousands) Outstanding as of April 30, 2019 ​ 193 ​ $ 25.48 Granted ​ 230 ​ ​ 21.56 Vested ​ (67) ​ ​ 25.59 Forfeited ​ (40) ​ ​ 25.29 Outstanding as of October 31, 2019 ​ 316 ​ $ 22.60 ​ As of October 31, 2019, there was $5.3 million of total unrecognized compensation cost related to nonvested restricted stock units. That cost is expected to be recognized over a weighted-average period of 2.2 years. Employee Stock Purchase Plan ​ The Company has an employee stock purchase plan (“ESPP”), the terms of which allow for qualified employees to participate in the purchase of shares of the Company’s common stock at a price equal to 90% of the lower of the closing price at the beginning or end of the purchase period, which is a six-month period ending on December 31 and June 30 of each year. During the six months ended October 31, 2019, 0.1 million shares of the Company’s common stock were purchased under the ESPP at an average price of $13.37 per share. The Company recognized $0.3 million and $0.2 million of stock-based compensation expense during the six months ended October 31, 2019 and 2018, respectively, related to the ESPP.

Stock Appreciation Rights, Defe

Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests	6 Months Ended
	Oct. 31, 2019
Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests
Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests	10. Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests The following table presents a summary of changes to the liabilities for stock appreciation rights, deferred compensation and redeemable noncontrolling interests for the six months ended October 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock ​ ​ ​ ​ Redeemable ​ ​ Appreciation ​ Deferred ​ Noncontrolling ​ Rights Compensation Interests ​ ​ (in thousands) Balance as of April 30, 2019 ​ $ 23,458 ​ $ 1,695 ​ $ 12,498 Amounts redeemed ​ (825) ​ (108) ​ (4,644) Change in fair value ​ 1,327 ​ 94 ​ 550 Balance as of October 31, 2019 ​ $ 23,960 ​ $ 1,681 ​ $ 8,404 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Classified as current as of April 30, 2019 ​ $ 1,355 ​ $ 108 ​ $ 1,569 Classified as long-term as of April 30, 2019 ​ ​ 22,103 ​ ​ 1,587 ​ ​ 10,929 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Classified as current as of October 31, 2019 ​ $ 821 ​ $ — ​ $ — Classified as long-term as of October 31, 2019 ​ ​ 23,139 ​ ​ 1,681 ​ ​ 8,404 ​ Total expense related to these instruments was $2.0 million and $1.8 million during the six months ended October 31, 2019 and 2018, respectively, and was included in selling, general and administrative expenses in the Condensed Consolidated Statements of Operations and Comprehensive Income. Stock Appreciation Rights Certain subsidiaries have granted stock appreciation rights to certain employees under which payments are dependent on the appreciation in the book value per share, adjusted for certain provisions, of the applicable subsidiary. Settlements of the awards can be made in a combination of cash or installment notes, generally paid over five years, upon a triggering event. As of October 31, 2019, all stock appreciation rights were vested. Deferred Compensation Subsidiaries’ stockholders have entered into other deferred compensation agreements that granted the stockholders a payment based on a percentage in excess of book value, adjusted for certain provisions, upon an occurrence as defined in the related agreements, which are called “Buy Sell” agreements. These instruments are redeemed in cash or installment notes, generally paid in annual installments over the five years following termination of employment. Redeemable Noncontrolling Interests Noncontrolling interests were issued to certain employees of certain of the Company’s subsidiaries. All of the noncontrolling interest awards are subject to mandatory redemption on termination of employment for any reason. These instruments are redeemed in cash or installment notes, generally paid in annual installments over the five years following termination of employment. Liabilities related to these agreements are classified as share-based liability awards and are measured at fair value. Under the terms of the employee agreements, the redemption value is determined based on the book value of the subsidiary, as adjusted for certain items. Upon the termination of employment or other triggering events including death or disability of the noncontrolling stockholders in the Company’s subsidiaries, we are obligated to purchase, or redeem, the noncontrolling interests at either an agreed upon price or a formula value provided in the stockholder agreements. This formula value is typically based on the book value per share of the subsidiary’s equity, including certain adjustments.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Oct. 31, 2019
Fair Value Measurements
Fair Value Measurements	11. Fair Value Measurements Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents the estimated carrying amount and fair value of the Company’s assets and liabilities measured at fair value on a recurring basis as of October 31, 2019 and April 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ ​ 2019 ​ 2019 ​ ​ (in thousands) Liabilities: ​ ​ ​ ​ ​ Interest rate swap (Level 2) ​ $ 18,265 ​ $ 5,613 Stock appreciation rights (Level 3) ​ ​ 23,960 ​ ​ 23,458 Deferred compensation (Level 3) ​ ​ 1,681 ​ 1,695 Noncontrolling interest holders (Level 3) ​ ​ 8,404 ​ ​ 12,498 Contingent consideration (Level 3) ​ ​ 12,991 ​ 12,354 ​ Derivative instruments convert the variable interest rate on its First Lien Facility to a fixed 1-month LIBOR interest rate . The contracts were effective on and terminate on as a cash flow hedges. The derivative instruments are classified in other liabilities in the Condensed Consolidated Balance Sheets as of October 31, 2019 and April 30, 2019. ​ The fair value of derivative instruments is determined using Level 2 inputs. Generally, the Company obtains the Level 2 inputs from its counterparties. Substantially all of the inputs are observable in the marketplace throughout the full term of the instruments, which can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. The fair value of the Company’s interest rate swap was determined using widely accepted valuation techniques including a discounted cash flow analysis on the expected cash flows of the derivative. This analysis reflected the contractual terms of the derivatives, including the period to maturity, and used observable market-based inputs, including interest rate curves and implied volatilities. ​ Stock appreciation rights, deferred compensation and redeemable noncontrolling interests Contingent consideration Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis Disclosures are required for certain assets and liabilities that are measured at fair value on a nonrecurring basis in periods subsequent to initial recognition. Such measurements of fair value relate primarily to assets and liabilities measured at fair value in connection with business combinations and long-lived asset impairments. For more information on business combinations, see Note 3, “Business Acquisitions.” There were no material long-lived asset impairments during the six months ended October 31, 2019 or 2018.

Transactions With Related Parti

Transactions With Related Parties	6 Months Ended
	Oct. 31, 2019
Transactions With Related Parties
Transactions With Related Parties	12. Transactions With Related Parties The Company purchases inventories from Southern Wall Products, Inc. (“SWP”) on a continuing basis. During the three and six months ended October 31, 2019, certain executive officers and stockholders of the Company were stockholders of SWP, which was spun-off from Gypsum Management and Supply, Inc. on August 31, 2012. The Company purchased inventory from SWP for distribution in the amount of $3.7 million and $3.5 million during the three months ended October 31, 2019 and 2018, respectively, and $7.3 million and $7.0 million during the six months ended October 31, 2019 and 2018, respectively. Amounts due to SWP for purchases of inventory for distribution were $1.3 million and $1.2 million as of October 31, 2019 and April 30, 2019, respectively, and are included in accounts payable in the Condensed Consolidated Balance Sheets.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Oct. 31, 2019
Commitments and Contingencies
Commitments and Contingencies	13. Commitments and Contingencies ​ The Company is a defendant in various lawsuits and administrative actions associated with personal injuries, claims of former employees, and other events arising in the normal course of business. As discussed in Note 1 “—Insurance Liabilities”, the Company records liabilities for these claims, and assets for amounts recoverable from the insurer, for these claims covered by insurance. ​

Segments

Segments	6 Months Ended
	Oct. 31, 2019
Segments
Segments	14. Segments General The Company has seven operating segments based on geographic operations that it aggregates into one reportable segment. The Company defines operating segments as components of the organization for which discrete financial information is available and operating results are evaluated on a regular basis by the Chief Operating Decision Maker (“CODM”) in order to assess performance and allocate resources. The Company’s CODM is its Chief Executive Officer. The Company determined it has seven operating segments based on the Company’s seven geographic divisions, which are Central, Midwest, Northeast, Southern, Southeast, Western and Canada. The Company aggregates its operating segments into a single reportable segment based on similarities between the operating segments’ economic characteristics, nature of products sold, production process, type of customer and methods of distribution. The accounting policies of the operating segments are the same as those described in the summary of significant policies. In addition to the Company’s reportable segment, the Company’s consolidated results include both corporate activities and certain other activities. Corporate includes the Company’s corporate office building and support services provided to its subsidiaries. Other includes Tool Source Warehouse, Inc., which functions primarily as an internal distributor of tools. Segment Results The CODM assesses the Company’s performance based on the periodic review of net sales, Adjusted EBITDA and certain other measures for each of the operating segments. Adjusted EBITDA is not a recognized financial measure under GAAP. However, we believe it assists investors and analysts in comparing our operating performance across reporting periods on a consistent basis by excluding items that we do not believe are indicative of our core operating performance. Management believes Adjusted EBITDA is helpful in highlighting trends in our operating results, while other measures can differ significantly depending on long-term strategic decisions regarding capital structure, the tax jurisdictions in which companies operate and capital investments. In addition, we utilize Adjusted EBITDA in certain calculations under the ABL Facility and the First Lien Facility. The ABL Facility and the First Lien Facility permit us to make certain additional adjustments in calculating Consolidated EBITDA, such as projected net cost savings, which are not reflected in the Adjusted EBITDA data presented in this Quarterly Report on Form 10-Q. See “Management’s Discussion and Analysis of Financial Condition and Results of Operations -- Non-GAAP Financial Measures” for a further discussion of this non-GAAP measure. The following tables present segment results for the three and six months ended October 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended October 31, 2019 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 854,853 ​ $ 281,900 ​ $ 29,024 ​ $ 89,171 Other ​ ​ 7,076 ​ 2,593 ​ 55 ​ ​ 734 Corporate ​ ​ — ​ — ​ 439 ​ ​ — ​ ​ $ 861,929 ​ $ 284,493 ​ $ 29,518 ​ $ 89,905 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended October 31, 2018 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 827,198 ​ $ 265,815 ​ $ 30,062 ​ $ 86,450 Other ​ 6,639 ​ 2,335 ​ 55 ​ ​ 695 Corporate ​ — ​ — ​ 670 ​ ​ — ​ ​ $ 833,837 ​ $ 268,150 ​ $ 30,787 ​ $ 87,145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended October 31, 2019 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 1,695,010 ​ $ 553,254 ​ $ 57,956 ​ $ 172,254 Other ​ 14,095 ​ 4,893 ​ 108 ​ ​ 1,239 Corporate ​ — ​ — ​ 729 ​ ​ — ​ ​ $ 1,709,105 ​ $ 558,147 ​ $ 58,793 ​ $ 173,493 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended October 31, 2018 ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 1,598,748 ​ $ 508,390 ​ $ 55,916 ​ $ 161,044 Other ​ 13,233 ​ 4,576 ​ 113 ​ 1,373 Corporate ​ — ​ — ​ 1,080 ​ — ​ ​ $ 1,611,981 ​ $ 512,966 ​ $ 57,109 ​ $ 162,417 ​ The following table presents a reconciliation of Adjusted EBITDA to net income for the three and six months ended October 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 2018 ​ 2019 ​ 2018 ​ ​ (in thousands) Net income ​ $ 29,138 ​ $ 24,912 ​ $ 53,958 ​ $ 33,562 Interest expense ​ 17,559 ​ 19,182 ​ 35,836 ​ 35,370 Write-off of debt discount and deferred financing fees ​ ​ 707 ​ ​ — ​ ​ 707 ​ ​ — Interest income ​ (6) ​ 203 ​ (18) ​ (33) Provision for income taxes ​ 7,927 ​ 8,059 ​ 15,517 ​ 10,895 Depreciation expense ​ 12,592 ​ 11,538 ​ 25,014 ​ 22,148 Amortization expense ​ 16,926 ​ 19,249 ​ 33,779 ​ 34,961 Stock appreciation expense(a) ​ ​ 1,267 ​ ​ 649 ​ ​ 1,327 ​ ​ 983 Redeemable noncontrolling interests(b) ​ (18) ​ 282 ​ 644 ​ 813 Equity-based compensation(c) ​ 2,315 ​ 1,094 ​ 3,710 ​ 1,498 Severance and other permitted costs(d) ​ 1,394 ​ 882 ​ 1,948 ​ 5,718 Transaction costs (acquisitions and other)(e) ​ 327 ​ 841 ​ 1,299 ​ 5,594 Gain on sale of assets ​ (586) ​ (173) ​ (742) ​ (294) Effects of fair value adjustments to inventory(f) ​ — ​ — ​ 151 ​ 4,129 Change in fair value of financial instruments(g) ​ — ​ 376 ​ — ​ 6,395 Secondary public offering costs(h) ​ ​ 363 ​ ​ — ​ ​ 363 ​ ​ — Debt transaction costs(i) ​ ​ — ​ ​ 51 ​ ​ — ​ ​ 678 Adjusted EBITDA ​ $ 89,905 ​ $ 87,145 ​ $ 173,493 ​ $ 162,417 (a) Represents non-cash expense related to stock appreciation rights agreements. (b) Represents non-cash compensation expense related to changes in the fair values of noncontrolling interests . (c) Represents non-cash equity-based compensation expense related to the issuance of share-based awards. (d) Represents severance expenses and other costs permitted in calculations under the ABL Facility and the First Lien Facility. (e) Represents costs related to acquisitions paid to third parties. (f) Represents the non-cash cost of sales impact of purchase accounting adjustments to increase inventory to its estimated fair value. (g) Represents the mark-to-market adjustments for derivative financial instruments. (h) Represents costs paid to third-party advisors related to secondary offerings of our common stock. (i) Represents costs paid to third-party advisors related to debt refinancing activities. During the six months ended October 31, 2019, the Company recorded operating lease ROU assets as a result of the adoption of the new lease guidance. The Company’s geographic divisions, other and corporate segments, recorded $113.3 million, $0.3 million and $5.2 million, respectively, of operating lease ROU assets as of the transition date. Revenues by Product The following table presents the Company’s net sales to external customers by main product lines for the three and six months ended October 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ ​ 2019 ​ 2018 ​ 2019 2018 ​ ​ (in thousands) Wallboard $ 350,618 $ 334,688 $ 692,213 ​ $ 652,423 Ceilings ​ 122,807 118,376 251,917 234,231 Steel framing ​ 136,159 135,760 267,988 264,872 Other products ​ 252,345 245,013 496,987 460,455 Total net sales ​ $ 861,929 $ 833,837 $ 1,709,105 $ 1,611,981 ​ Geographic Information ​ The following table presents the Company’s net sales by major geographic area for the three and six months ended October 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 2018 ​ 2019 2018 ​ ​ (in thousands) United States ​ $ 744,134 $ 706,347 ​ $ 1,475,477 $ 1,397,078 Canada ​ 117,795 127,490 ​ 233,628 214,903 Total net sales ​ $ 861,929 $ 833,837 ​ $ 1,709,105 $ 1,611,981 ​ Net sales for Canada for the six months ended October 31, 2019 includes six months of net sales compared to five months for the six months ended October 31, 2018 due to the Company’s acquisition of Titan on June 1, 2018. The average exchange rates for translating Canada net sales from Canadian dollars to U.S. dollars were 0.7547 and 0.7533 for the three and six months ended October 31, 2019, respectively. The average exchange rates were and 0.7697 and 0.7679 for the three and five months ended October 31, 2018, respectively. The following table presents the Company’s property and equipment, net, by major geographic area as of October 31, 2019 and April 30, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ 2019 2019 ​ ​ (in thousands) United States ​ $ 259,589 ​ $ 249,857 Canada ​ 32,547 32,492 Total property and equipment, net ​ $ 292,136 $ 282,349 ​

Earnings Per Common Share

Earnings Per Common Share	6 Months Ended
	Oct. 31, 2019
Earnings Per Common Share
Earnings Per Common Share	15. Earnings Per Common Share The following table sets forth the computation of basic and diluted earnings per share of common stock for the three and six months ended October 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 ​ 2018 2019 2018 ​ ​ (in thousands, except per share data) Net income ​ $ 29,138 ​ $ 24,912 ​ $ 53,958 ​ $ 33,562 Less: Net income allocated to participating securities ​ ​ - ​ ​ 665 ​ ​ 342 ​ ​ 751 Net income attributable to common stockholders ​ $ 29,138 $ 24,247 ​ $ 53,616 ​ $ 32,811 Basic earnings per common share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic weighted average common shares outstanding ​ 41,761 ​ 41,149 ​ 41,382 ​ 41,121 Basic earnings per common share ​ $ 0.70 ​ $ 0.59 ​ $ 1.30 ​ $ 0.80 Diluted earnings per common share: ​ ​ ​ ​ Basic weighted average common shares outstanding ​ 41,761 ​ 41,149 ​ 41,382 ​ 41,121 Add: Common Stock Equivalents ​ 874 ​ 769 ​ 744 ​ 875 Diluted weighted average common shares outstanding ​ 42,635 ​ 41,918 ​ 42,126 ​ 41,996 Diluted earnings per common share ​ $ 0.68 ​ $ 0.58 ​ $ 1.27 ​ $ 0.78 ​ ​ ​ ​

Subsequent Event

Subsequent Event	6 Months Ended
	Oct. 31, 2019
Subsequent Event
Subsequent Event	16. Subsequent Event ​ On November 1, 2019, the Company acquired Rigney Building Supplies Ltd. (“Rigney”). Rigney distributes interior building products, as well as masonry and landscaping products, through a single location in Kingston, Ontario. ​ ​ ​

Business, Basis of Presentati_2

Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Oct. 31, 2019
Business, Basis of Presentation and Summary of Significant Accounting Policies
Basis of Presentation	Basis of Presentation ​ The condensed consolidated financial statements included in this Quarterly Report on Form 10-Q have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) that permit reduced disclosure for interim periods. In the opinion of management, the accompanying unaudited condensed consolidated financial statements contain all normal and recurring adjustments necessary for a fair presentation of the results of operations, financial position and cash flows. All adjustments are of a normal recurring nature unless otherwise disclosed. The results of operations for interim periods are not necessarily indicative of results for any other interim period or the entire fiscal year. As a result, the unaudited condensed consolidated financial statements should be read in conjunction with our audited consolidated financial statements included in our Annual Report on Form 10-K for the fiscal year ended April 30, 2019. ​
Principles of Consolidation	Principles of Consolidation ​ The condensed consolidated financial statements present the results of operations, financial position, stockholders’ equity and cash flows of the Company and its subsidiaries. All material intercompany balances and transactions have been eliminated in consolidation. The results of operations of businesses acquired are included from their respective dates of acquisition. ​
Use of Estimates	Use of Estimates ​ The preparation of financial statements in conformity with Generally Accepted Accounting Principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. ​
Foreign Currency Translation	Foreign Currency Translation ​ Assets and liabilities of the Company’s Canadian subsidiaries are translated at the exchange rate prevailing at the balance sheet date, while income and expenses are translated at average rates for the period. Translation gains and losses are reported as a separate component of stockholders’ equity and other comprehensive income. Gains and losses on foreign currency transactions are recognized in the Condensed Consolidated Statements of Operations and Comprehensive Income within other income, net. ​
Insurance Liabilities	Insurance Liabilities ​ The Company is self-insured for certain losses related to medical claims. The Company has stop-loss coverage to limit the exposure arising from medical claims. In addition, the Company has deductible-based insurance policies for certain losses related to general liability, automobile and workers’ compensation. The deductible amount per incident is $0.3 million, $0.5 million and $1.0 million for general liability, workers’ compensation and automobile, respectively. The coverage consists of a primary layer and an excess layer. The primary layer of coverage is from $0.5 million to $2.0 million and the excess layer cover claims from $2.0 million to $100.0 million. The expected ultimate cost for claims incurred as of the balance sheet date is not discounted and is recognized as a liability. Insurance losses for claims filed and claims incurred but not reported are accrued based upon estimates of the aggregate liability for uninsured claims using loss development factors, actuarial assumptions and historical loss development experience. ​ As of October 31, 2019 and April 30, 2019, the aggregate liabilities for medical self-insurance were $3.9 million and $3.4 million, respectively, and are included in other accrued expenses and current liabilities in the Condensed Consolidated Balance Sheets. As of October 31, 2019 and April 30, 2019, reserves for general liability, automobile and workers’ compensation totaled approximately $23.8 million and $17.7 million, respectively, and are included in other accrued expenses and current liabilities and other liabilities in the Condensed Consolidated Balance Sheets. As of October 31, 2019 and April 30, 2019, expected recoveries for medical self-insurance, general liability, automobile and workers’ compensation totaled approximately $10.3 million and $6.0 million, respectively, and are included in prepaid expenses and other current assets and other assets in the Condensed Consolidated Balance Sheets. ​
Income Taxes	Income Taxes ​ The Company considers each interim period an integral part of the annual period and measures tax expense (benefit) using an estimated annual effective income tax rate. Estimates of the annual effective income tax rate at the end of interim periods are, out of necessity, based on evaluation of possible future events and transactions and may be subject to subsequent refinement or revision. The Company forecasts its estimated annual effective income tax rate and then applies that rate to its year-to-date pre-tax ordinary income (loss), subject to certain loss limitation provisions. In addition, certain specific transactions are excluded from the Company’s estimated annual effective tax rate computation, but are discretely recognized within income tax expense (benefit) in their respective interim period. Future changes in the forecasted annual income (loss) projections, tax rate changes, or discrete tax items could result in significant adjustments to quarterly income tax expense (benefit) in future periods. ​ The Company evaluates its deferred tax assets quarterly to determine if valuation allowances are required. In this evaluation, the Company considers both positive and negative evidence in determining whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The primary negative evidence considered includes the cumulative operating losses generated in prior periods. The primary positive evidence considered includes the reversal of deferred tax liabilities primarily related to depreciation and amortization that would occur within the same jurisdiction and during the carryforward period necessary to absorb the federal and state net operating losses and other deferred tax assets. ​ Deferred tax assets and liabilities are computed by applying the federal, provincial and state income tax rates in effect to the gross amounts of temporary differences and other tax attributes, such as net operating loss carry-forwards. In assessing if the deferred tax assets will be realized, the Company considers whether it is more likely than not that some or all of these deferred tax assets will be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the period in which these deductible temporary differences reverse. ​
Fair Value of Financial Instruments	Fair Value of Financial Instruments ​ Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Authoritative guidance for fair value measurements establishes a three-level hierarchy that prioritizes the inputs to valuation models based upon the degree to which they are observable. The three levels of the fair value measurement hierarchy are as follows: ​ Level 1 Inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the reporting entity can access at the measurement date. Level 2 Inputs are inputs other than quoted prices included within Level 1 that are observable for the asset or liability, either directly or indirectly. Level 3 Inputs are unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. ​ The carrying values of the Company’s cash, cash equivalents, trade receivables and trade payables approximate their fair values because of their short-term nature. Based on borrowing rates available to the Company for loans with similar terms, the carrying values of the Company’s debt instruments approximate fair value. See Note 11, “Fair Value Measurements,” for additional information with respect to the Company’s fair value measurements. ​
Earnings Per Share	Earnings Per Share ​ Basic earnings per share is computed by dividing net income available to common stockholders by the weighted average number of outstanding shares of common stock for the period. Diluted earnings per share reflects the potential dilution that could occur if securities or other contracts to issue common stock, including stock options and restricted stock units (collectively “Common Stock Equivalents”), were exercised or converted into common stock. The dilutive effect of outstanding stock options and restricted stock units is reflected in diluted earnings per share by application of the treasury stock method. In applying the treasury stock method for stock-based compensation arrangements, the assumed proceeds are computed as the sum of the amount the employee must pay upon exercise and the amount of compensation cost attributed to future services and not yet recognized. Diluted earnings per share is computed by increasing the weighted-average number of outstanding shares of common stock computed in basic earnings per share to include the dilutive effect of Common Stock Equivalents for the period. In periods of net loss, the number of shares used to calculate diluted loss per share is the same as basic net loss per share. ​ The holders of the Company’s Exchangeable Shares (as defined in Note 8, “Stockholders’ Equity”) were entitled to receive dividends or distributions that are equal to any dividends or distributions on the Company’s common stock. As a result, when the Exchangeable Shares were outstanding, they were classified as a participating security and thereby required the allocation of income that would have otherwise been available to common stockholders when calculating earnings per share. Diluted earnings per share is calculated by utilizing the most dilutive result of the if-converted and two-class methods. In both methods, net income attributable to common stockholders and the weighted-average common shares outstanding are adjusted to account for the impact of the assumed issuance of potential common shares that are dilutive, subject to dilution sequencing rules. ​
Recent Accounting Pronouncements	Recently Adopted Accounting Pronouncements ​ Leases – ​ On July 30, 2018, the FASB issued new guidance that provided entities with an additional (and optional) transition method to adopt the new lease standard. Under this new transition method, an entity initially applies the new lease standard at the adoption date and recognizes a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption. ​ The Company adopted the new lease standard on May 1, 2019 using the optional transition method. The Company elected the package of practical expedients permitted in the guidance, which among other things, allows the Company to carry forward the historical accounting relating to lease identification and classification for existing leases upon adoption. The Company also elected to use the practical expedient to not separate lease and nonlease components. The Company did not elect the hindsight practical expedient. The Company made an accounting policy election to keep leases with an initial term of 12 months or less off the Consolidated Balance Sheet. ​ The adoption of the standard resulted in the recording of operating lease ROU assets and operating lease liabilities of $118.8 million on the Condensed Consolidated Balance Sheet as of the adoption date. The Company also reclassified deferred rent of $4.8 million from liabilities into its operating lease ROU assets. The adoption did not have a material impact on the Company’s Statement of Operations or Statement of Cash Flows. See Note 6, “Leases,” for information and disclosures regarding leases. ​ Recently Issued Accounting Pronouncements ​ Credit Losses – ​ Goodwill ​ Fair Value Measurement Disclosures –

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	6 Months Ended
	Oct. 31, 2019
Goodwill and Intangible Assets
Schedule of changes in the carrying amount of goodwill	​ ​ ​ ​ ​ ​ Carrying ​ ​ Amount ​ ​ (in thousands) Balance as of April 30, 2019 ​ $ 617,327 Goodwill acquired ​ ​ 877 Translation adjustment ​ 3,712 Balance as of October 31, 2019 ​ $ 621,916
Schedule of components of definite-lived intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ Weighted ​ October 31, 2019 ​ ​ Useful ​ Average ​ Gross ​ ​ ​ Net ​ ​ Lives ​ Amortization ​ Carrying ​ Accumulated ​ Carrying ​ (years) Period Amount Amortization Value ​ ​ (dollars in thousands) Customer relationships ​ 5 - 16 ​ 12.8 ​ $ 527,556 ​ $ 245,252 ​ $ 282,304 Definite-lived tradenames ​ 5 - 20 ​ 16.3 ​ 56,637 ​ 8,843 ​ 47,794 Vendor agreements ​ 8 - 10 ​ 8.3 ​ 6,644 ​ 4,164 ​ 2,480 Developed technology ​ 5 ​ 4.9 ​ ​ 5,318 ​ ​ 1,532 ​ ​ 3,786 Leasehold interests ​ 1 - 15 ​ 7.6 ​ 3,724 ​ 1,875 ​ 1,849 Other ​ 3 - 5 ​ 3.4 ​ ​ 4,175 ​ ​ 1,846 ​ ​ 2,329 Totals ​ ​ ​ ​ ​ $ 604,054 ​ $ 263,512 ​ $ 340,542 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Estimated ​ Weighted ​ April 30, 2019 ​ ​ Useful ​ Average ​ Gross ​ ​ ​ Net ​ ​ Lives Amortization Carrying Accumulated Carrying ​ (years) Period Amount Amortization Value ​ ​ (dollars in thousands) Customer relationships ​ 5 - 16 ​ 12.8 ​ $ 520,703 ​ $ 214,044 ​ $ 306,659 Definite-lived tradenames ​ 5 - 20 ​ 16.3 ​ 56,018 ​ 6,993 ​ 49,025 Vendor agreements ​ 8 - 10 ​ 8.3 ​ 6,644 ​ 3,761 ​ 2,883 Developed technology ​ 5 ​ 4.9 ​ ​ 5,209 ​ ​ 971 ​ ​ 4,238 Leasehold interests ​ 1 - 15 ​ 7.6 ​ 3,707 ​ 1,502 ​ 2,205 Other ​ 3 - 5 ​ 3.4 ​ ​ 4,118 ​ ​ 1,182 ​ ​ 2,936 Totals ​ ​ ​ ​ ​ $ 596,399 ​ $ 228,453 ​ $ 367,946 ​

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Oct. 31, 2019
Long-Term Debt
Schedule of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ 2019 2019 ​ ​ (in thousands) First Lien Facility (1) (2) ​ $ 919,564 ​ $ 972,650 ABL Facility ​ 47,776 ​ 43,972 Finance lease obligations ​ 116,510 ​ 109,286 Installment notes at fixed rates up to 5.0%, due in monthly and annual installments through 2024 (3) ​ 16,198 ​ 15,287 Carrying value of debt ​ 1,100,048 ​ 1,141,195 Less current portion ​ 45,963 ​ 42,118 Long-term debt ​ $ 1,054,085 ​ $ 1,099,077 (1) Net of unamortized discount of $1,862 and $2,149 as of October 31, 2019 and April 30, 2019, respectively. (2) Net of deferred financing costs of $10,460 and $12,072 as of October 31, 2019 and April 30, 2019, respectively. (3) Net of unamortized discount of $1,276 and $1,200 as of October 31, 2019 and April 30, 2019, respectively.
Scheduled of maturities of long-term debt	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ First Lien ​ ​ ABL ​ Finance ​ Installment ​ ​ ​ ​ Facility(1) ​ Facility Leases Notes(2) ​ Total Years ending April 30, ​ (in thousands) 2020 (remaining six months) ​ $ 4,984 ​ $ — ​ $ 14,981 ​ $ 1,133 ​ $ 21,098 2021 ​ 9,968 ​ ​ — ​ ​ 30,761 ​ ​ 4,874 ​ 45,603 2022 ​ 9,968 ​ ​ — ​ ​ 27,560 ​ ​ 4,438 ​ 41,966 2023 ​ 9,968 ​ ​ — ​ ​ 22,001 ​ ​ 4,404 ​ 36,373 2024 ​ 9,968 ​ ​ — ​ ​ 14,895 ​ ​ 1,781 ​ 26,644 Thereafter ​ 887,030 ​ ​ 47,776 ​ ​ 6,312 ​ ​ 844 ​ 941,962 ​ ​ $ 931,886 ​ $ 47,776 ​ $ 116,510 ​ $ 17,474 ​ $ 1,113,646 (1) Gross of unamortized discount of $1,862 and deferred financing costs of $10,460 as of October 31, 2019. (2) Gross of unamortized discount of $1,276 as of October 31, 2019.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Oct. 31, 2019
Leases
Summary of components of lease expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months ​ Six Months ​ ​ Ended ​ Ended ​ ​ October 31, 2019 ​ October 31, 2019 ​ ​ (in thousands) Finance lease cost: ​ ​ ​ ​ ​ ​ Amortization of right-of-use assets ​ $ 6,054 ​ $ 12,113 Interest on lease liabilities ​ ​ 3,367 ​ ​ 6,789 Operating lease cost ​ ​ 10,289 ​ ​ 20,709 Variable lease cost ​ ​ 3,414 ​ ​ 6,613 Total lease cost ​ $ 23,124 ​ $ 46,224
Summary of components of supplemental cash flow information related to leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months ​ ​ ​ ​ ​ Ended ​ ​ ​ ​ ​ October 31, 2019 ​ ​ ​ ​ ​ (in thousands) Cash paid for amounts included in the measurement of lease liabilities ​ ​ ​ ​ ​ ​ Operating cash flows from operating leases ​ ​ ​ ​ $ 10,141 Operating cash flows from finance leases ​ ​ ​ ​ ​ 6,789 Financing cash flows from finance leases ​ ​ ​ ​ ​ 12,310 Right-of-use assets obtained in exchange for lease obligations ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 6,569 Finance leases ​ ​ ​ ​ ​ 22,812
Summary of other lease information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, 2019 ​ ​ ​ ​ ​ ​ ​ (in thousands) ​ Finance leases included in property and equipment ​ ​ ​ ​ ​ ​ ​ Property and equipment ​ ​ ​ ​ $ 149,769 ​ Accumulated depreciation ​ ​ ​ ​ ​ (34,513) ​ Property and equipment, net ​ ​ ​ ​ $ 115,256 ​ Weighted-average remaining lease term (years) ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 4.9 ​ Finance leases ​ ​ ​ ​ ​ 3.4 ​ Weighted-average discount rate ​ ​ ​ ​ ​ ​ ​ Operating leases ​ ​ ​ ​ ​ 5.5 % Finance leases ​ ​ ​ ​ ​ 5.4 %
Schedule of maturities for finance leases	​ ​ ​ ​ ​ ​ ​ ​ ​ Finance Operating Year Ended April 30, ​ (in thousands) 2020 (remaining six months) ​ $ 21,178 ​ $ 19,376 2021 ​ 40,387 ​ 32,481 2022 ​ 33,600 ​ 23,918 2023 ​ 24,855 ​ 17,591 2024 ​ 15,753 ​ 13,264 Thereafter ​ 6,471 ​ 23,016 Total lease payments ​ $ 142,244 ​ $ 129,646 Less imputed interest ​ 25,734 ​ 16,572 Total ​ $ 116,510 ​ $ 113,074
Schedule of maturities for operating leases	​ ​ ​ ​ ​ ​ ​ ​ ​ Finance Operating Year Ended April 30, ​ (in thousands) 2020 (remaining six months) ​ $ 21,178 ​ $ 19,376 2021 ​ 40,387 ​ 32,481 2022 ​ 33,600 ​ 23,918 2023 ​ 24,855 ​ 17,591 2024 ​ 15,753 ​ 13,264 Thereafter ​ 6,471 ​ 23,016 Total lease payments ​ $ 142,244 ​ $ 129,646 Less imputed interest ​ 25,734 ​ 16,572 Total ​ $ 116,510 ​ $ 113,074

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Oct. 31, 2019
Stockholders' Equity
Schedule of changes to accumulated other comprehensive loss, net of tax, by component	​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ Other ​ Comprehensive ​ ​ Loss ​ ​ (in thousands) Accumulated other comprehensive loss as of April 30, 2019 ​ $ (26,574) Foreign currency translation adjustments ​ ​ 11,451 Other comprehensive loss on derivative instruments ​ (9,667) Accumulated other comprehensive loss as of October 31, 2019 ​ $ (24,790)

Equity-Based Compensation - (Ta

Equity-Based Compensation - (Tables)	6 Months Ended
	Oct. 31, 2019
Equity-Based Compensation
Summary of stock option activity	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ ​ ​ Weighted ​ Average ​ ​ ​ ​ ​ ​ ​ Average ​ Remaining ​ Aggregate ​ ​ Number of ​ Exercise ​ Contractual ​ Intrinsic ​ ​ Options ​ Price ​ Life (years) ​ Value ​ ​ (shares and dollars in thousands) Outstanding as of April 30, 2019 2,080 ​ $ 16.34 6.15 $ 7,615 Options granted 380 ​ ​ 21.52 ​ Options exercised (534) ​ 12.65 ​ Options forfeited (102) ​ 25.59 ​ Options expired — ​ — ​ ​ Outstanding as of October 31, 2019 1,824 ​ $ 17.96 6.57 ​ $ 22,326 Exercisable as of October 31, 2019 1,242 ​ $ 15.32 5.35 ​ $ 18,354 Vested and expected to vest as of October 31, 2019 1,816 ​ $ 17.93 6.56 ​ $ 22,272
Schedule of weighted average assumptions used in Black-Scholes option-pricing model	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended ​ ​ October 31, ​ ​ 2019 ​ 2018 Volatility ​ 49.94 % ​ 33.71 % Expected life (years) ​ 6.0 ​ ​ 6.0 ​ Risk-free interest rate ​ 1.97 % ​ 2.87 % Dividend yield ​ — % ​ — %
Summary of restricted stock unity activity	​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ Number of ​ Average ​ ​ Restricted ​ Exercise ​ ​ Stock Units ​ Price ​ ​ (shares in thousands) Outstanding as of April 30, 2019 ​ 193 ​ $ 25.48 Granted ​ 230 ​ ​ 21.56 Vested ​ (67) ​ ​ 25.59 Forfeited ​ (40) ​ ​ 25.29 Outstanding as of October 31, 2019 ​ 316 ​ $ 22.60

Stock Appreciation Rights, De_2

Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests (Tables)	6 Months Ended
	Oct. 31, 2019
Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests
Summary of changes to liability for equity based compensation arrangements	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Stock ​ ​ ​ ​ Redeemable ​ ​ Appreciation ​ Deferred ​ Noncontrolling ​ Rights Compensation Interests ​ ​ (in thousands) Balance as of April 30, 2019 ​ $ 23,458 ​ $ 1,695 ​ $ 12,498 Amounts redeemed ​ (825) ​ (108) ​ (4,644) Change in fair value ​ 1,327 ​ 94 ​ 550 Balance as of October 31, 2019 ​ $ 23,960 ​ $ 1,681 ​ $ 8,404 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Classified as current as of April 30, 2019 ​ $ 1,355 ​ $ 108 ​ $ 1,569 Classified as long-term as of April 30, 2019 ​ ​ 22,103 ​ ​ 1,587 ​ ​ 10,929 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Classified as current as of October 31, 2019 ​ $ 821 ​ $ — ​ $ — Classified as long-term as of October 31, 2019 ​ ​ 23,139 ​ ​ 1,681 ​ ​ 8,404

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Oct. 31, 2019
Fair Value Measurements
Schedule of assets and liabilities measured at fair value on a recurring basis	​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ ​ 2019 ​ 2019 ​ ​ (in thousands) Liabilities: ​ ​ ​ ​ ​ Interest rate swap (Level 2) ​ $ 18,265 ​ $ 5,613 Stock appreciation rights (Level 3) ​ ​ 23,960 ​ ​ 23,458 Deferred compensation (Level 3) ​ ​ 1,681 ​ 1,695 Noncontrolling interest holders (Level 3) ​ ​ 8,404 ​ ​ 12,498 Contingent consideration (Level 3) ​ ​ 12,991 ​ 12,354

Segments (Tables)

Segments (Tables)	6 Months Ended
	Oct. 31, 2019
Segments
Schedule of segment results	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended October 31, 2019 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 854,853 ​ $ 281,900 ​ $ 29,024 ​ $ 89,171 Other ​ ​ 7,076 ​ 2,593 ​ 55 ​ ​ 734 Corporate ​ ​ — ​ — ​ 439 ​ ​ — ​ ​ $ 861,929 ​ $ 284,493 ​ $ 29,518 ​ $ 89,905 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended October 31, 2018 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 827,198 ​ $ 265,815 ​ $ 30,062 ​ $ 86,450 Other ​ 6,639 ​ 2,335 ​ 55 ​ ​ 695 Corporate ​ — ​ — ​ 670 ​ ​ — ​ ​ $ 833,837 ​ $ 268,150 ​ $ 30,787 ​ $ 87,145 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended October 31, 2019 ​ ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 1,695,010 ​ $ 553,254 ​ $ 57,956 ​ $ 172,254 Other ​ 14,095 ​ 4,893 ​ 108 ​ ​ 1,239 Corporate ​ — ​ — ​ 729 ​ ​ — ​ ​ $ 1,709,105 ​ $ 558,147 ​ $ 58,793 ​ $ 173,493 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Six Months Ended October 31, 2018 ​ ​ ​ ​ ​ Depreciation and ​ Adjusted ​ ​ Net Sales ​ Gross Profit ​ Amortization ​ EBITDA ​ ​ (in thousands) Geographic divisions ​ $ 1,598,748 ​ $ 508,390 ​ $ 55,916 ​ $ 161,044 Other ​ 13,233 ​ 4,576 ​ 113 ​ 1,373 Corporate ​ — ​ — ​ 1,080 ​ — ​ ​ $ 1,611,981 ​ $ 512,966 ​ $ 57,109 ​ $ 162,417
Reconciliation of Adjusted EBITDA to net income	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 2018 ​ 2019 ​ 2018 ​ ​ (in thousands) Net income ​ $ 29,138 ​ $ 24,912 ​ $ 53,958 ​ $ 33,562 Interest expense ​ 17,559 ​ 19,182 ​ 35,836 ​ 35,370 Write-off of debt discount and deferred financing fees ​ ​ 707 ​ ​ — ​ ​ 707 ​ ​ — Interest income ​ (6) ​ 203 ​ (18) ​ (33) Provision for income taxes ​ 7,927 ​ 8,059 ​ 15,517 ​ 10,895 Depreciation expense ​ 12,592 ​ 11,538 ​ 25,014 ​ 22,148 Amortization expense ​ 16,926 ​ 19,249 ​ 33,779 ​ 34,961 Stock appreciation expense(a) ​ ​ 1,267 ​ ​ 649 ​ ​ 1,327 ​ ​ 983 Redeemable noncontrolling interests(b) ​ (18) ​ 282 ​ 644 ​ 813 Equity-based compensation(c) ​ 2,315 ​ 1,094 ​ 3,710 ​ 1,498 Severance and other permitted costs(d) ​ 1,394 ​ 882 ​ 1,948 ​ 5,718 Transaction costs (acquisitions and other)(e) ​ 327 ​ 841 ​ 1,299 ​ 5,594 Gain on sale of assets ​ (586) ​ (173) ​ (742) ​ (294) Effects of fair value adjustments to inventory(f) ​ — ​ — ​ 151 ​ 4,129 Change in fair value of financial instruments(g) ​ — ​ 376 ​ — ​ 6,395 Secondary public offering costs(h) ​ ​ 363 ​ ​ — ​ ​ 363 ​ ​ — Debt transaction costs(i) ​ ​ — ​ ​ 51 ​ ​ — ​ ​ 678 Adjusted EBITDA ​ $ 89,905 ​ $ 87,145 ​ $ 173,493 ​ $ 162,417 (a) Represents non-cash expense related to stock appreciation rights agreements. (b) Represents non-cash compensation expense related to changes in the fair values of noncontrolling interests . (c) Represents non-cash equity-based compensation expense related to the issuance of share-based awards. (d) Represents severance expenses and other costs permitted in calculations under the ABL Facility and the First Lien Facility. (e) Represents costs related to acquisitions paid to third parties. (f) Represents the non-cash cost of sales impact of purchase accounting adjustments to increase inventory to its estimated fair value. (g) Represents the mark-to-market adjustments for derivative financial instruments. (h) Represents costs paid to third-party advisors related to secondary offerings of our common stock. (i) Represents costs paid to third-party advisors related to debt refinancing activities.
Schedule of net sales to external customers by main product lines	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ ​ 2019 ​ 2018 ​ 2019 2018 ​ ​ (in thousands) Wallboard $ 350,618 $ 334,688 $ 692,213 ​ $ 652,423 Ceilings ​ 122,807 118,376 251,917 234,231 Steel framing ​ 136,159 135,760 267,988 264,872 Other products ​ 252,345 245,013 496,987 460,455 Total net sales ​ $ 861,929 $ 833,837 $ 1,709,105 $ 1,611,981
Schedule of net sales by major geographic area	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 2018 ​ 2019 2018 ​ ​ (in thousands) United States ​ $ 744,134 $ 706,347 ​ $ 1,475,477 $ 1,397,078 Canada ​ 117,795 127,490 ​ 233,628 214,903 Total net sales ​ $ 861,929 $ 833,837 ​ $ 1,709,105 $ 1,611,981
Schedule of long-lived assets by major geographic area	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ October 31, ​ April 30, ​ 2019 2019 ​ ​ (in thousands) United States ​ $ 259,589 ​ $ 249,857 Canada ​ 32,547 32,492 Total property and equipment, net ​ $ 292,136 $ 282,349

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Oct. 31, 2019
Earnings Per Common Share
Schedule of computation of basic and diluted earnings per share of common stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ Six Months Ended ​ ​ October 31, ​ October 31, ​ 2019 ​ 2018 2019 2018 ​ ​ (in thousands, except per share data) Net income ​ $ 29,138 ​ $ 24,912 ​ $ 53,958 ​ $ 33,562 Less: Net income allocated to participating securities ​ ​ - ​ ​ 665 ​ ​ 342 ​ ​ 751 Net income attributable to common stockholders ​ $ 29,138 $ 24,247 ​ $ 53,616 ​ $ 32,811 Basic earnings per common share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic weighted average common shares outstanding ​ 41,761 ​ 41,149 ​ 41,382 ​ 41,121 Basic earnings per common share ​ $ 0.70 ​ $ 0.59 ​ $ 1.30 ​ $ 0.80 Diluted earnings per common share: ​ ​ ​ ​ Basic weighted average common shares outstanding ​ 41,761 ​ 41,149 ​ 41,382 ​ 41,121 Add: Common Stock Equivalents ​ 874 ​ 769 ​ 744 ​ 875 Diluted weighted average common shares outstanding ​ 42,635 ​ 41,918 ​ 42,126 ​ 41,996 Diluted earnings per common share ​ $ 0.68 ​ $ 0.58 ​ $ 1.27 ​ $ 0.78

Business, Basis of Presentati_3

Business, Basis of Presentation and Summary of Significant Accounting Policies - Business (Details)	6 Months Ended
	Oct. 31, 2019item
Minimum
Business
Number of distribution centers	250

Business, Basis of Presentati_4

Business, Basis of Presentation and Summary of Significant Accounting Policies - Insurance Liabilities (Details) - USD ($) $ in Millions	Oct. 31, 2019	Apr. 30, 2019
Other accrued expenses and current liabilities.
Insurance Liabilities
Aggregate liabilities for medical self-insurance	$ 3.9	$ 3.4
General liability
Insurance Liabilities
Deductible amount	0.3
Workers' compensation
Insurance Liabilities
Deductible amount	0.5
Automobile
Insurance Liabilities
Deductible amount	1
General liability, workers' compensation and automobile | Other accrued expenses and current liabilities.
Insurance Liabilities
Reserve for insurance	23.8	17.7
General liability, workers' compensation and automobile | Prepaid expenses and other current assets
Insurance Liabilities
Insurance recovery receivable	10.3	$ 6
General liability, workers' compensation and automobile | Minimum
Insurance Liabilities
Primary layer of insurance coverage	0.5
Excess layer of insurance coverage	2
General liability, workers' compensation and automobile | Maximum
Insurance Liabilities
Primary layer of insurance coverage	2
Excess layer of insurance coverage	$ 100

Business, Basis of Presentati_5

Business, Basis of Presentation and Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	May 01, 2019	Oct. 31, 2019
Adoption of new accounting pronouncement
Operating lease right-of-use assets		$ 107,624
Operating lease liability		113,074
Operating lease right-of-use assets obtained in exchange for lease obligations		$ 6,569
Adjustment | ASU 2016-02
Adoption of new accounting pronouncement
Operating lease right-of-use assets	$ 118,800
Operating lease liability	118,800
Operating lease right-of-use assets obtained in exchange for lease obligations	$ 4,800

Revenue (Details)

Revenue (Details) - USD ($) $ in Millions	6 Months Ended
	Oct. 31, 2019	Apr. 30, 2019
Revenue
Revenue, Practical Expedient, Financing Component [true false]	true
Revenue, Practical Expedient, Remaining Performance Obligation [true/false]	true
Receivables from contracts with customers	$ 454.6	$ 431.4

Business Acquisitions (Details)

Business Acquisitions (Details) - Hart Acoustical and Drywall Supply	Jun. 03, 2019location
San Antonio
Acquisition of Titan
Number of locations	2
La Feria
Acquisition of Titan
Number of locations	1

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Goodwill (Details) $ in Thousands	6 Months Ended
	Oct. 31, 2019USD ($)
Carrying Amount of Goodwill
Balance	$ 617,327
Goodwill acquired	877
Translation adjustment	3,712
Balance	$ 621,916

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Definite-Lived Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Oct. 31, 2019	Apr. 30, 2019
Definite-lived intangible assets
Gross Carrying Amount	$ 604,054	$ 596,399
Accumulated Amortization	263,512	228,453
Net Carrying Value	$ 340,542	$ 367,946
Customer relationships
Definite-lived intangible assets
Weighted Average Amortization Period (in years)	12 years 9 months 18 days	12 years 9 months 18 days
Gross Carrying Amount	$ 527,556	$ 520,703
Accumulated Amortization	245,252	214,044
Net Carrying Value	$ 282,304	$ 306,659
Customer relationships | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Customer relationships | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	16 years	16 years
Tradenames
Definite-lived intangible assets
Weighted Average Amortization Period (in years)	16 years 3 months 18 days	16 years 3 months 18 days
Gross Carrying Amount	$ 56,637	$ 56,018
Accumulated Amortization	8,843	6,993
Net Carrying Value	$ 47,794	$ 49,025
Tradenames | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Tradenames | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	20 years	20 years
Vendor agreements
Definite-lived intangible assets
Weighted Average Amortization Period (in years)	8 years 3 months 18 days	8 years 3 months 18 days
Gross Carrying Amount	$ 6,644	$ 6,644
Accumulated Amortization	4,164	3,761
Net Carrying Value	$ 2,480	$ 2,883
Vendor agreements | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	8 years	8 years
Vendor agreements | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	10 years	10 years
Developed technology
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years
Weighted Average Amortization Period (in years)	4 years 10 months 24 days	4 years 10 months 24 days
Gross Carrying Amount	$ 5,318	$ 5,209
Accumulated Amortization	1,532	971
Net Carrying Value	$ 3,786	$ 4,238
Leasehold interests
Definite-lived intangible assets
Weighted Average Amortization Period (in years)	7 years 7 months 6 days	7 years 7 months 6 days
Gross Carrying Amount	$ 3,724	$ 3,707
Accumulated Amortization	1,875	1,502
Net Carrying Value	$ 1,849	$ 2,205
Leasehold interests | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	1 year	1 year
Leasehold interests | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	15 years	15 years
Other intangible assets
Definite-lived intangible assets
Weighted Average Amortization Period (in years)	3 years 4 months 24 days	3 years 4 months 24 days
Gross Carrying Amount	$ 4,175	$ 4,118
Accumulated Amortization	1,846	1,182
Net Carrying Value	$ 2,329	$ 2,936
Other intangible assets | Minimum
Definite-lived intangible assets
Estimated Useful Lives (years)	3 years	3 years
Other intangible assets | Maximum
Definite-lived intangible assets
Estimated Useful Lives (years)	5 years	5 years

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Amortization (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Intangible assets
Amortization expense	$ 16,926	$ 19,249	$ 33,779	$ 34,961
Depreciation and amortization expense
Intangible assets
Amortization expense	$ 16,900	$ 19,200	$ 33,800	$ 35,000

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Estimated Aggregate Amortization Expense (Details) $ in Millions	Oct. 31, 2019USD ($)
Estimated aggregate future amortization expense
Expense remainder of fiscal year	$ 31.5
2021	55.4
2022	46.4
2023	38.7
2024	31.5
Thereafter	$ 137

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Indefinite-Lived Intangible Assets (Details) - USD ($) $ in Millions	Oct. 31, 2019	Jul. 31, 2019	Apr. 30, 2019
Goodwill and Intangible Assets
Tradenames	$ 61.4	$ 61.4	$ 61.4

Long-Term Debt - Components (De

Long-Term Debt - Components (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Long-term debt
Carrying value of debt	$ 1,100,048	$ 1,141,195
Less current portion	45,963	42,118
Long-term debt	1,054,085	1,099,077
First Lien Loan
Long-term debt
Carrying value of debt	919,564	972,650
Unamortized discount	1,862	2,149
Deferred financing costs	10,460	12,072
ABL Facility
Long-term debt
Carrying value of debt	47,776	43,972
Finance lease obligations
Long-term debt
Carrying value of debt	116,510	109,286
Installment notes
Long-term debt
Carrying value of debt	$ 16,198	$ 15,287
Interest rate	5.00%	5.00%
Unamortized discount	$ 1,276	$ 1,200

Long-Term Debt - Acquisition De

Long-Term Debt - Acquisition Debt (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	6 Months Ended
	Sep. 30, 2019	Oct. 31, 2019	Oct. 31, 2019
Long-term debt
Write-off of debt discount and deferred financing fees		$ 707	$ 707
First Lien Loan
Long-term debt
Aggregate principal amount		$ 919,600	$ 919,600
Percentage of quarterly principal payments			0.25%
Write-off of debt discount and deferred financing fees	$ 700
Borrowing interest rate (as a percent)		4.54%	4.54%
Repayments of Debt	$ 50,000
First Lien Loan | LIBOR
Long-term debt
Margin added to variable rate (as a percent)			2.75%
Variable rate floor (as a percent)			0.00%

Long-Term Debt - Asset-Based Le

Long-Term Debt - Asset-Based Lending Facility (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Sep. 30, 2019	Sep. 29, 2019
Long-term debt
Net borrowings	$ 562,698	$ 623,117
ABL Facility
Long-term debt
Maximum amount under the facility			$ 445,000	$ 345,000
Borrowing interest rate (as a percent)	3.91%
Available borrowings under the facility	$ 387,600
Net borrowings	$ 3,800
ABL Facility | Swing-line
Long-term debt
Maximum amount under the facility			$ 34,500

Long-Term Debt - Titan Revolvin

Long-Term Debt - Titan Revolving Credit Facility (Details) - Titan Facility $ in Millions, $ in Millions	Oct. 31, 2019USD ($)	Jun. 01, 2018USD ($)	Jun. 01, 2018CAD ($)
Debt Instrument [Line Items]
Maximum amount under the facility		$ 22.8	$ 30
Available borrowings under the facility	$ 22.8

Long-Term Debt - Maturities (De

Long-Term Debt - Maturities (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Debt maturities
2020 (remaining six months)	$ 21,098
2021	45,603
2022	41,966
2023	36,373
2024	26,644
Thereafter	941,962
Total	1,113,646
First Lien Loan
Debt maturities
2020 (remaining six months)	4,984
2021	9,968
2022	9,968
2023	9,968
2024	9,968
Thereafter	887,030
Total	931,886
Long Term Debt
Unamortized discount	1,862	$ 2,149
Deferred financing costs	10,460	12,072
ABL Facility
Debt maturities
Thereafter	47,776
Total	47,776
Finance lease obligations
Debt maturities
2020 (remaining six months)	14,981
2021	30,761
2022	27,560
2023	22,001
2024	14,895
Thereafter	6,312
Total	116,510
Installment notes
Debt maturities
2020 (remaining six months)	1,133
2021	4,874
2022	4,438
2023	4,404
2024	1,781
Thereafter	844
Total	17,474
Long Term Debt
Unamortized discount	$ 1,276	$ 1,200

Leases (Details)

Leases (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Oct. 31, 2019USD ($)	Oct. 31, 2019USD ($)
Leases
Option to extend		true
Finance lease cost:
Amortization of right-of-use assets	$ 6,054	$ 12,113
Interest on lease liabilities	3,367	6,789
Operating lease cost	10,289	20,709
Variable lease cost	3,414	6,613
Total lease cost	$ 23,124	$ 46,224
Minimum
Leases
Lease term (in years)	1 year	1 year
Renewal lease term (in years)	1 year	1 year
Maximum
Leases
Lease term (in years)	11 years	11 years
Renewal lease term (in years)	5 years	5 years

Leases - Supplemental cash flow

Leases - Supplemental cash flow information (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	$ 10,141
Operating cash flows from finance leases	6,789
Financing cash flows from finance leases	12,310	$ 8,820
Right-of-use assets obtained in exchange for lease obligations - Operating leases	6,569
Right-of-use assets obtained in exchange for lease obligations - Finance leases	$ 22,812

Leases - Other information (Det

Leases - Other information (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Finance leases included in property and equipment
Accumulated depreciation	$ (140,608)	$ (123,583)
Property and equipment, net	$ 292,136	$ 282,349
Weighted-average remaining lease term (years) - Operating leases	4 years 10 months 24 days
Weighted-average remaining lease term (years) - Finance leases	3 years 4 months 24 days
Weighted-average discount rate - Operating leases	5.50%
Weighted-average discount rate - Finance leases	5.40%
Finance Leased Assets
Finance leases included in property and equipment
Property and equipment	$ 149,769
Accumulated depreciation	(34,513)
Property and equipment, net	$ 115,256

Leases - Future minimum lease p

Leases - Future minimum lease payments under non-cancellable leases (Details) $ in Thousands	Oct. 31, 2019USD ($)
Finance lease
2020 (remaining six months)	$ 21,178
2021	40,387
2022	33,600
2023	24,855
2024	15,753
Thereafter	6,471
Total lease payments	142,244
Less imputed interest	25,734
Total	116,510
Operating lease
2020 (remaining six months)	19,376
2021	32,481
2022	23,918
2023	17,591
2024	13,264
Thereafter	23,016
Total lease payments	129,646
Less imputed interest	16,572
Total	$ 113,074

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Apr. 30, 2019
Effective income tax rate (as a percent)	22.30%	24.50%
Reserve for uncertain tax positions	$ 0		$ 0
Valuation allowance	$ 1.2		$ 1.1
Domestic
Federal statutory rate (as a percent)	21.00%

Stockholders' Equity - Exchange

Stockholders' Equity - Exchangeable Shares, Share Repurchase Program and Secondary Public Offering (Details) $ / shares in Units, shares in Millions, $ in Millions	Sep. 09, 2019$ / sharesshares	Jun. 13, 2019shares	Jun. 01, 2018shares	Oct. 31, 2019USD ($)	Nov. 30, 2018USD ($)
Exchangeable Shares and Share Repurchase Program
Remaining amount under repurchase program | $				$ 58.5
AEA Investors LP | Selling Stockholders
Exchangeable Shares and Share Repurchase Program
Shares sold	6.8
Price to the public (in dollars per share) | $ / shares	$ 27.20
Maximum
Exchangeable Shares and Share Repurchase Program
Stock repurchase program, authorized amount | $					$ 75
Titan
Exchangeable Shares and Share Repurchase Program
Issuance of shares to current shareholders of Titan (in shares)			1.1
Exchangeable shares converted		1.1
Exchangeable shares conversion ratio			1
Duration which stock can not be transferred			1 year

Stockholders' Equity - Accumula

Stockholders' Equity - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Stockholders' Equity
Balance			$ 629,176	$ 579,451
Foreign currency translation adjustments	$ (409)	$ (4,902)	11,451	(8,693)
Balance	696,039	641,258	696,039	641,258
Other comprehensive loss on derivative instruments before reclassification, tax			3,000
Accumulated Other Comprehensive Income (Loss)
Stockholders' Equity
Balance			(26,574)	441
Foreign currency translation adjustments			11,451	(8,693)
Other comprehensive loss on derivative instruments			(9,667)
Balance	$ (24,790)	$ (7,762)	$ (24,790)	$ (7,762)

Equity-Based Compensation - Sto

Equity-Based Compensation - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Apr. 30, 2019
Other disclosures
Equity-based compensation	$ 2,315	$ 1,094	$ 3,710	$ 1,498
Selling, general and administrative expenses
Other disclosures
Equity-based compensation			$ 3,400	1,300
Stock Options
Number of Options
Outstanding, beginning of the period (in shares)			2,080
Options granted (in shares)			380
Options exercised (in shares)			(534)
Options forfeited (in shares)			(102)
Outstanding, end of the period (in shares)	1,824		1,824		2,080
Exercisable at end of period (in shares)	1,242		1,242
Vested and expected to vest at end of period (in shares)	1,816		1,816
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share)			$ 16.34
Options granted (in dollars per share)			21.52
Options exercised (in dollars per share)			12.65
Options forfeited (in dollars per share)			25.59
Outstanding, end of the period (in dollars per share)	$ 17.96		17.96		$ 16.34
Exercisable at end of period (in dollars per share)	15.32		15.32
Vested and expected to vest at end of period (in dollars per share)	$ 17.93		$ 17.93
Other disclosures
Weighted Average Remaining Contractual Life, Outstanding (in years)			6 years 6 months 25 days		6 years 1 month 24 days
Weighted Average Remaining Contractual Life, Exercisable at end of period (in years)			5 years 4 months 6 days
Weighted Average Remaining Contractual Life, Vested and expected to vest at end of period (in years)			6 years 6 months 21 days
Aggregate Intrinsic Value, Outstanding	$ 22,326		$ 22,326		$ 7,615
Aggregate Intrinsic Value, Exercisable at end of period	18,354		18,354
Aggregate Intrinsic Value, Vested and expected to vest at end of period	22,272		22,272
Intrinsic value of options exercised			8,600	$ 700
Unrecognized compensation cost	$ 4,600		$ 4,600
Weighted-average period for recognition of unrecognized compensation expense (in years)			2 years 4 months 24 days

Equity-Based Compensation - Bla

Equity-Based Compensation - Black Scholes Options - Pricing Model (Details) - Stock Options - $ / shares	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Stock options
Volatility (as a percent)	49.94%	33.71%
Expected life (years)	6 years	6 years
Risk-free interest rate (as a percent)	1.97%	2.87%
Dividend yield (as a percent)	0.00%	0.00%
Weighted average grant date fair value (in dollars per share)	$ 10.55	$ 9.72

Equity-Based Compensation - Res

Equity-Based Compensation - Restricted Stock Units (Details) - Restricted stock units $ / shares in Units, shares in Thousands, $ in Millions	6 Months Ended
	Oct. 31, 2019USD ($)$ / sharesshares
Number of Restricted Stock Units
Outstanding, beginning of the period (in shares) | shares	193
Granted (in shares) | shares	230
Vested (in shares) | shares	(67)
Forfeited (in shares) | shares	(40)
Outstanding, end of the period (in shares) | shares	316
Weighted Average Exercise Price
Outstanding, beginning of period (in dollars per share) | $ / shares	$ 25.48
Granted (in dollars per share) | $ / shares	21.56
Vested (in dollars per share) | $ / shares	25.59
Forfeited (in dollars per share) | $ / shares	25.29
Outstanding, end of the period (in dollars per share) | $ / shares	$ 22.60
Unrecognized compensation cost | $	$ 5.3
Weighted-average period for recognition of unrecognized compensation expense (in years)	2 years 2 months 12 days

Equity-Based Compensation - Emp

Equity-Based Compensation - Employee Stock Purchase Plan (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 2,315	$ 1,094	$ 3,710	$ 1,498
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of common stock price based on closing price at the beginning or end of the last day of the purchase period			90.00%
Purchase period			6 months
Number of shares purchased under ESPP			0.1
Average price per share	$ 13.37		$ 13.37
Share-based compensation expense			$ 300	$ 200

Stock Appreciation Rights, De_3

Stock Appreciation Rights, Deferred Compensation and Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Apr. 30, 2019
Selling, general and administrative expenses
Equity based compensation arrangements
Expense related to equity based compensation arrangements	$ 2,000	$ 1,800
Stock Appreciation Rights
Equity based compensation arrangements
Award liability as of beginning of period	23,458
Amounts redeemed	(825)
Change in fair value	1,327
Award liability as of end of period	23,960
Current liabilities related to plans	821		$ 1,355
Long-term liabilities related to plans	$ 23,139		22,103
Settlement period	5 years
Deferred Compensation
Equity based compensation arrangements
Award liability as of beginning of period	$ 1,695
Amounts redeemed	(108)
Change in fair value	94
Award liability as of end of period	1,681
Current liabilities related to plans			108
Long-term liabilities related to plans	$ 1,681		1,587
Settlement period	5 years
Redeemable Noncontrolling Interests
Equity based compensation arrangements
Award liability as of beginning of period	$ 12,498
Amounts redeemed	(4,644)
Change in fair value	550
Award liability as of end of period	8,404
Current liabilities related to plans			1,569
Long-term liabilities related to plans	$ 8,404		$ 10,929
Settlement period	5 years

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Apr. 30, 2019	Feb. 28, 2019
Fair Value, Measurements, Recurring | Level 3
Fair Value Measurements
Stock appreciation rights	$ 23,960	$ 23,458
Deferred compensation	1,681	1,695
Noncontrolling interest holders	8,404	12,498
Contingent consideration	12,991	12,354
Interest rate cap | Fair Value, Measurements, Recurring | Level 2
Fair Value Measurements
Derivative liabilities	18,265	$ 5,613
Interest rate swap agreements | First Lien Loan
Derivative instruments
Notional amount			$ 500,000
Interest rate swap agreements | LIBOR | First Lien Loan
Derivative instruments
Fixed interest rate			2.46%
Selling, general and administrative expenses | Titan
Fair Value Measurements
Contingent consideration expense	$ 400

Transactions With Related Par_2

Transactions With Related Parties - Purchased Inventories (Details) - Southern Wall Products, Inc. - Inventory purchases - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	Apr. 30, 2019
Transactions with related parties
Purchases from related party	$ 3.7	$ 3.5	$ 7.3	$ 7
Accounts payable
Transactions with related parties
Due to SWP	$ 1.3		$ 1.3		$ 1.2

Segments (Details)

Segments (Details)	6 Months Ended
	Oct. 31, 2019segmentdivision
Segments
Number of operating segments	7
Number of reportable segments	1
Number of geographic divisions | division	7

Segments - Net Sales, Adjusted

Segments - Net Sales, Adjusted EBITDA and Certain Other Measures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018	May 01, 2019
Segment information
Net sales	$ 861,929	$ 833,837	$ 1,709,105	$ 1,611,981
Gross Profit	284,493	268,150	558,147	512,966
Depreciation and Amortization	29,518	30,787	58,793	57,109
Adjusted EBITDA	89,905	87,145	173,493	162,417
Operating lease right-of-use assets	107,624		107,624
Geographic divisions
Segment information
Net sales	854,853	827,198	1,695,010	1,598,748
Gross Profit	281,900	265,815	553,254	508,390
Depreciation and Amortization	29,024	30,062	57,956	55,916
Adjusted EBITDA	89,171	86,450	172,254	161,044
Operating lease right-of-use assets					$ 113,300
Other.
Segment information
Net sales	7,076	6,639	14,095	13,233
Gross Profit	2,593	2,335	4,893	4,576
Depreciation and Amortization	55	55	108	113
Adjusted EBITDA	734	695	1,239	1,373
Operating lease right-of-use assets					300
Corporate
Segment information
Depreciation and Amortization	$ 439	$ 670	$ 729	$ 1,080
Operating lease right-of-use assets					$ 5,200

Segments - Reconciliation of Ne

Segments - Reconciliation of Net Income to Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Segments
Net income	$ 29,138	$ 24,912	$ 53,958	$ 33,562
Interest expense	17,559	19,182	35,836	35,370
Write-off of debt discount and deferred financing fees	707		707
Interest income	(6)	203	(18)	(33)
Provision for income taxes	7,927	8,059	15,517	10,895
Depreciation expense	12,592	11,538	25,014	22,148
Amortization expense	16,926	19,249	33,779	34,961
Stock appreciation expense	1,267	649	1,327	983
Redeemable noncontrolling interests	(18)	282	644	813
Equity-based compensation	2,315	1,094	3,710	1,498
Severance and other permitted costs	1,394	882	1,948	5,718
Transaction costs (acquisitions and other)	327	841	1,299	5,594
Gain on sale of assets	(586)	(173)	(742)	(294)
Effects of fair value adjustments to inventory			151	4,129
Change in fair value of financial instruments		376		6,395
Secondary public offering costs	363		363
Debt transaction costs		51		678
Adjusted EBITDA	$ 89,905	$ 87,145	$ 173,493	$ 162,417

Segments - Net Sales by Main Pr

Segments - Net Sales by Main Product Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Revenue from external customers
Total net sales	$ 861,929	$ 833,837	$ 1,709,105	$ 1,611,981
Wallboard
Revenue from external customers
Total net sales	350,618	334,688	692,213	652,423
Ceilings
Revenue from external customers
Total net sales	122,807	118,376	251,917	234,231
Steel framing
Revenue from external customers
Total net sales	136,159	135,760	267,988	264,872
Other products
Revenue from external customers
Total net sales	$ 252,345	$ 245,013	$ 496,987	$ 460,455

Segments - Net sales by major g

Segments - Net sales by major geographic area (Details) $ in Thousands	3 Months Ended		5 Months Ended	6 Months Ended
	Oct. 31, 2019USD ($)$ / $	Oct. 31, 2018USD ($)$ / $	Oct. 31, 2018$ / $	Oct. 31, 2019USD ($)$ / $	Oct. 31, 2018USD ($)
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 861,929	$ 833,837		$ 1,709,105	$ 1,611,981
Average exchange rates | $ / $	0.7547	0.7697	0.7679	0.7533
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 744,134	$ 706,347		$ 1,475,477	1,397,078
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total net sales	$ 117,795	$ 127,490		$ 233,628	$ 214,903

Segments - Property and equipme

Segments - Property and equipment, net, by major geographic area (Details) - USD ($) $ in Thousands	Oct. 31, 2019	Apr. 30, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 292,136	$ 282,349
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	259,589	249,857
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Property and equipment, net	$ 32,547	$ 32,492

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		6 Months Ended
		Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2019	Oct. 31, 2018
Computation of basic and diluted earnings per share of common stock
Net income		$ 29,138	$ 24,912	$ 53,958	$ 33,562
Less: Net income allocated to participating securities			665	342	751
Net income attributable to common stockholders		$ 29,138	$ 24,247	$ 53,616	$ 32,811
Basic earnings per common share:
Basic weighted average common shares outstanding (in shares)		41,761	41,149	41,382	41,121
Basic earnings per common share (in dollars per share)	[1]	$ 0.70	$ 0.59	$ 1.30	$ 0.80
Diluted earnings per common share:
Basic weighted average common shares outstanding (in shares)		41,761	41,149	41,382	41,121
Add: Common Stock Equivalents		874	769	744	875
Diluted weighted average common shares outstanding (in shares)		42,635	41,918	42,126	41,996
Diluted earnings per common share (in dollars per share)	[1]	$ 0.68	$ 0.58	$ 1.27	$ 0.78
[1]	See Note 15 for detailed calculations