Advanced Drainage Systems (WMS) 10-K 1 Jun 20 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	May 19, 2020	Sep. 30, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Mar. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	ADVANCED DRAINAGE SYSTEMS, INC.
Entity Central Index Key	0001604028
Current Fiscal Year End Date	--03-31
Entity Incorporation, State or Country Code	DE
Entity File Number	001-36557
Entity Tax Identification Number	51-0105665
Entity Address, Address Line One	4640 Trueman Boulevard
Entity Address, City or Town	Hilliard
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	43026
City Area Code	614
Local Phone Number	658-0050
Document Annual Report	true
Document Transition Report	false
Entity Well-known Seasoned Issuer	No
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		69,338,180
Entity Public Float			$ 1,540
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of Each Class	Common Stock, $0.01 par value per share
Trading Symbol(s)	WMS
Name of Each Exchange On Which Registered	NYSE
Documents Incorporated by Reference	Part III of this report incorporates by reference specific portions of the Registrant’s Notice of Annual Meeting and Proxy Statement relating to the Annual Meeting of Stockholders to be held on July 23, 2020.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Current assets:
Cash	$ 174,233	$ 8,891
Receivables (less allowance for doubtful accounts of $5,035 and $7,653, respectively)	200,028	186,991
Inventories	282,398	264,540
Other current assets	9,552	6,091
Total current assets	666,211	466,513
Property, plant and equipment, net	481,380	398,891
Other assets:
Goodwill	597,819	102,638
Intangible assets, net	555,338	37,177
Other assets	69,140	36,940
Total assets	2,369,888	1,042,159
Current liabilities:
Current maturities of debt obligations	7,955	25,932
Current maturities of finance lease obligations	20,382	23,117
Accounts payable	106,710	93,577
Other accrued liabilities	101,116	61,901
Accrued income taxes	2,050	1,758
Total current liabilities	238,213	206,285
Long-term debt obligation (less unamortized debt issuance costs of $2,419 and $2,293, respectively)	1,089,368	208,602
Long-term finance lease obligations	44,501	61,555
Deferred tax liabilities	175,616	45,963
Other liabilities	37,608	19,119
Total liabilities	1,585,306	541,524
Commitments and contingencies (see Note 15)
Mezzanine equity:
Redeemable convertible preferred stock: $0.01 par value; 47,070 shares authorized; 44,170 shares issued; 21,562 and 22,611 shares outstanding, respectively	269,529	282,638
Deferred compensation — unearned ESOP shares	(22,432)	(180,316)
Total mezzanine equity	247,097	102,322
Stockholders’ equity:
Common stock: $0.01 par value; 1,000,000 shares authorized; 69,810 and 57,964 shares issued, respectively; 69,319 and 57,490 shares outstanding, respectively	11,555	11,436
Paid-in capital	827,573	391,039
Common stock in treasury, at cost	(10,461)	(9,863)
Accumulated other comprehensive loss	(35,325)	(25,867)
Retained earnings (deficit)	(267,619)	17,582
Total ADS stockholders’ equity	525,723	384,327
Noncontrolling interest in subsidiaries	11,762	13,986
Total stockholders’ equity	537,485	398,313
Total liabilities, mezzanine equity and stockholders’ equity	$ 2,369,888	$ 1,042,159

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Allowance for doubtful accounts	$ 5,035	$ 7,653
Unamortized debt issuance costs	$ 2,419	$ 2,293
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares issued	69,810,000	57,964,000
Common stock, shares outstanding	69,319,000	57,490,000
Redeemable Convertible Preferred Stock [Member]
Mezzanine equity, par value	$ 0.01	$ 0.01
Mezzanine equity, shares authorized	47,070,000	47,070,000
Mezzanine equity, shares issued	44,170,000	44,170,000
Mezzanine equity, shares outstanding	21,562,000	22,611,000

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Net sales	$ 1,673,805	$ 1,384,733	$ 1,330,354
Cost of goods sold	1,188,716	1,057,766	1,027,873
Cost of goods sold - ESOP special dividend compensation	168,610
Gross profit	316,479	326,967	302,481
Operating expenses:
Selling	117,068	96,335	92,764
General and administrative	154,270	89,692	98,392
Loss on disposal of assets and costs from exit and disposal activities	5,338	3,647	15,003
Intangible amortization	57,010	7,880	8,068
(Loss) income from operations	(95,349)	129,413	88,254
Other expense:
Interest expense	82,711	18,618	15,262
Derivative loss (gains) and other expense (income), net	1,554	(815)	(3,950)
(Loss) income before income taxes	(179,614)	111,610	76,942
Income tax expense	14,092	30,049	11,411
Equity in net (income) loss of unconsolidated affiliates	(1,909)	95	739
Net (loss) income	(191,797)	81,466	64,792
Less: net income attributable to noncontrolling interest	1,377	3,694	2,785
Net (loss) income attributable to ADS	$ (193,174)	$ 77,772	$ 62,007
Weighted average common shares outstanding:
Basic	63,820	57,025	55,696
Diluted	63,820	57,611	56,334
Net (loss) income per share available to common stockholders:
Basic	$ (3.21)	$ 1.23	$ 1
Diluted	$ (3.21)	$ 1.22	$ 0.99
ESOP special dividend compensation [Member]
Operating expenses:
Selling, general and administrative - ESOP special dividend compensation	$ 78,142

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (191,797)	$ 81,466	$ 64,792
Currency translation (loss) gain	(12,324)	(5,749)	3,886
Comprehensive (loss) income	(204,121)	75,717	68,678
Less: other comprehensive (loss) gain attributable to noncontrolling interest, net of tax	(2,866)	(1,129)	318
Less: net income attributable to noncontrolling interest	1,377	3,694	2,785
Total comprehensive (loss) income attributable to ADS	$ (202,632)	$ 73,152	$ 65,575

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Cash Flows from Operating Activities
Net income	$ (191,797)	$ 81,466	$ 64,792
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	124,940	71,900	75,003
Deferred income taxes	(2,924)	12,813	(11,239)
Loss on disposal of assets and costs from exit and disposal activities	5,338	3,647	12,655
ESOP and stock-based compensation	32,395	21,828	18,845
ESOP special dividend compensation	246,752
Amortization of deferred financing charges	34,476	735	934
Inventory step up related to Infiltrator Water Technologies acquisition	7,880
Fair market value adjustments to derivatives	3,128	2,346	(3,244)
Equity in net loss of unconsolidated affiliates	(1,909)	95	739
Other operating activities	(6,005)	(5,219)	1,010
Changes in working capital:
Receivables	5,170	(17,953)	(4,327)
Inventories	19,086	(2,034)	(4,841)
Prepaid expenses and other current assets	(1,929)	(1,004)	1,648
Accounts payable, accrued expenses and other liabilities	31,588	(16,942)	(14,855)
Net cash provided by operating activities	306,189	151,678	137,120
Cash Flows from Investing Activities
Capital expenditures	(67,677)	(43,412)	(41,709)
Acquisition of Infiltrator Water Technologies, net of cash acquired	(1,089,322)
Other investing activities	6,529	868	11,264
Net cash used in investing activities	(1,150,470)	(42,544)	(30,445)
Cash Flows from Financing Activities
Proceeds from Term Loan Facility	1,300,000
Payments on Term Loan Facility	(1,300,000)		(72,500)
Proceeds from syndication of Term Loan Facility	700,000
Payments on syndicated Term Loan Facility	(51,750)
Proceeds from Senior Notes	350,000		75,000
Proceeds from Credit Agreement	277,900
Payments on Credit Agreement	(177,900)
Debt issuance costs	(34,606)		(2,268)
Payments on Prudential Senior Notes	(100,000)	(25,000)	(25,000)
Payments of notes, mortgages, and other debt		(940)	(1,905)
Payments on finance lease obligations	(27,119)	(24,284)	(24,214)
Proceeds from common stock offering, net of offering costs	293,648
Acquisition of noncontrolling interest in BaySaver		(8,821)
Cash dividends paid	(92,127)	(26,148)	(18,478)
Proceeds from option exercises	8,163	5,908	9,087
Repurchase of common stock			(7,947)
Other financing activities	(237)	(1,270)	(2,428)
Net cash provided by (used in) financing activities	1,011,572	(117,655)	(94,953)
Effect of exchange rate changes on cash	(1,949)	(175)	(585)
Net change in cash	165,342	(8,696)	11,137
Cash at beginning of year	8,891	17,587	6,450
Cash at end of year	174,233	8,891	17,587
PNC Credit Agreement [Member]
Cash Flows from Financing Activities
Proceeds from Credit Agreement	253,900	405,700	487,850
Payments on Credit Agreement	$ (388,300)	$ (442,800)	$ (512,150)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Paid-In Capital [Member]	Common Stock in Treasury [Member]	Accumulated Other Comprehensive Loss [Member]	Retained (Deficit) Earnings [Member]	Total ADS Stockholders' Equity [Member]	Non-controlling Interest in Subsidiaries [Member]
Beginning Balance, Value at Mar. 31, 2017	$ 237,610	$ 12,393	$ 755,787	$ (436,984)	$ (24,815)	$ (83,678)	$ 222,703	$ 14,907
Beginning Balance, Shares at Mar. 31, 2017		153,560		98,222
Net (loss) income	63,935					62,007	62,007	1,928
Other comprehensive gain (loss)	3,886				3,568		3,568	318
Redeemable convertible preferred stock dividends	(1,724)					(1,724)	(1,724)
Common stock dividend	(15,685)					(15,685)	(15,685)
Dividend paid to noncontrolling interest holder	(490)							(490)
Allocation of ESOP shares to participants for Compensation	3,809		3,809				3,809
Allocation of ESOP shares to participants for Dividend	(134)					(134)	(134)
Exercise of common stock options	9,087	$ 7	9,161	$ (81)			9,087
Exercise of common stock options, Shares		666		2
Restricted stock awards	154	$ 1		$ 153			154
Restricted stock awards, Shares		90		(72)
Stock-based compensation	6,812		6,812				6,812
Reclassification of liability-classified awards	13,714		13,714				13,714
ESOP distributions in common stock	11,566	$ 2	9,811	$ 1,753			11,566
ESOP distributions in common stock, Shares		318		(394)
Retirement of common stock held in treasury		$ (977)	(433,852)	$ 434,829
Retirement of common stock held in treasury, Shares		(97,745)		(97,745)
Common stock repurchases	(7,947)			$ (7,947)			(7,947)
Common stock repurchases, Shares				400
Accretion of redeemable noncontrolling interest	(334)		(334)				(334)
Ending Balance, Value at Mar. 31, 2018	324,259	$ 11,426	364,908	$ (8,277)	(21,247)	(39,214)	307,596	16,663
Ending Balance, Shares at Mar. 31, 2018		56,889		413
Net (loss) income	80,634					77,772	77,772	2,862
Other comprehensive gain (loss)	(5,749)				(4,620)		(4,620)	(1,129)
Redeemable convertible preferred stock dividends	(1,913)					(1,913)	(1,913)
Common stock dividend	(18,336)					(18,336)	(18,336)
Dividend paid to noncontrolling interest holder	(4,410)							(4,410)
Allocation of ESOP shares to participants for Compensation	5,712		5,712				5,712
Allocation of ESOP shares to participants for Dividend	(134)					(134)	(134)
Exercise of common stock options	4,540	$ 4	5,908	$ (1,372)			4,540
Exercise of common stock options, Shares		420		52
Restricted stock awards	(213)	$ 1		$ (214)			(213)
Restricted stock awards, Shares		127		9
Stock-based compensation	6,532		6,532				6,532
ESOP distributions in common stock	8,609	$ 5	8,604				8,609
ESOP distributions in common stock, Shares		528
Acquisition of noncontrolling interest in BaySaver	(1,218)		(625)			(593)	(1,218)
Ending Balance, Value at Mar. 31, 2019	398,313	$ 11,436	391,039	$ (9,863)	(25,867)	17,582	384,327	13,986
Ending Balance, Shares at Mar. 31, 2019		57,964		474
Net (loss) income	(191,797)					(193,174)	(193,174)	1,377
Other comprehensive gain (loss)	(12,324)				(9,458)		(9,458)	(2,866)
Redeemable convertible preferred stock dividends	(10,847)					(10,847)	(10,847)
Common stock dividend	(80,821)					(80,821)	(80,821)
Dividend paid to noncontrolling interest holder	(735)							(735)
Allocation of ESOP shares to participants for Compensation	8,164		8,164				8,164
Allocation of ESOP shares to participants for Dividend	(359)					(359)	(359)
Special Dividend	101,189		101,189				101,189
Exercise of common stock options	7,962	$ 6	8,163	$ (207)			7,962
Exercise of common stock options, Shares		571		7
Restricted stock awards	(390)	$ 1		$ (391)			(390)
Restricted stock awards, Shares		118		10
Stock-based compensation	12,269		12,269				12,269
ESOP distributions in common stock	13,109	$ 8	13,101				13,109
ESOP distributions in common stock, Shares		807
Common Stock Offering, Value	293,648	$ 104	293,544				293,648
Common Stock Offering, Shares		10,350
Other	104		104				104
Ending Balance, Value at Mar. 31, 2020	$ 537,485	$ 11,555	$ 827,573	$ (10,461)	$ (35,325)	$ (267,619)	$ 525,723	$ 11,762
Ending Balance, Shares at Mar. 31, 2020		69,810		491

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Deficit) (Parenthetical) - $ / shares	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Statement Of Stockholders Equity [Abstract]
Common stock dividend per share	$ 1.36	$ 0.32	$ 0.28

Consolidated Statements of Mezz

Consolidated Statements of Mezzanine Equity - USD ($) shares in Thousands, $ in Thousands	Total	Redeemable Convertible Preferred Stock [Member]	Deferred Compensation - Unearned ESOP Shares [Member]	Total Mezzanine Equity [Member]	Redeemable Non-Controlling Interest in Subsidiaries [Member]
Beginning Balance, Value at Mar. 31, 2017		$ 302,814	$ (198,216)	$ 112,825	$ 8,227
Beginning Balance, Shares at Mar. 31, 2017		24,225	15,863
Net (loss) income				857	857
Redeemable convertible preferred stock dividends	$ (1,724)
Common stock dividend	(15,685)
Dividend paid to noncontrolling interest holder	(490)			(613)	(613)
Allocation of ESOP shares to participants for Compensation	3,809		$ 8,048	8,048
Allocation of ESOP shares to participants for Compensation, Shares			(644)
Allocation of ESOP shares to participants for Dividend	134
Exercise of common stock options	9,087
Restricted stock awards	154
ESOP distributions in common stock		$ (11,567)		(11,567)
ESOP distributions in common stock, Shares		(925)
Accretion of redeemable noncontrolling interest	334
Ending Balance, Value at Mar. 31, 2018		$ 291,247	$ (190,168)	109,550	8,471
Ending Balance, Shares at Mar. 31, 2018		23,300	15,219
Net (loss) income				832	832
Redeemable convertible preferred stock dividends	(1,913)
Common stock dividend	(18,336)
Dividend paid to noncontrolling interest holder	(4,410)			(1,075)	(1,075)
Allocation of ESOP shares to participants for Compensation	5,712		$ 9,584	9,584
Allocation of ESOP shares to participants for Compensation, Shares			(767)
Allocation of ESOP shares to participants for Dividend	134		$ 268	268
Exercise of common stock options	4,540
Restricted stock awards	(213)
ESOP distributions in common stock		$ (8,609)		(8,609)
ESOP distributions in common stock, Shares		(689)
Acquisition of noncontrolling interest in BaySaver	(1,218)			(8,228)	$ (8,228)
Ending Balance, Value at Mar. 31, 2019	102,322	$ 282,638	$ (180,316)	102,322
Ending Balance, Shares at Mar. 31, 2019		22,611	14,452
Redeemable convertible preferred stock dividends	(10,847)
Common stock dividend	(80,821)
Dividend paid to noncontrolling interest holder	(735)
Allocation of ESOP shares to participants for Compensation	8,164		$ 11,962	11,962
Allocation of ESOP shares to participants for Compensation, Shares			(957)
Allocation of ESOP shares to participants for Dividend	359		$ 359	359
Special Dividend			$ 145,563	145,563
Special Dividend, shares			(11,645)
Exercise of common stock options	7,962
Restricted stock awards	(390)
ESOP distributions in common stock		$ (13,109)		(13,109)
ESOP distributions in common stock, Shares		(1,049)
Ending Balance, Value at Mar. 31, 2020	$ 247,097	$ 269,529	$ (22,432)	$ 247,097
Ending Balance, Shares at Mar. 31, 2020		21,562	1,850

Background and Summary of Signi

Background and Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Background and Summary of Significant Accounting Policies	1. BACKGROUND AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Description of Business - Advanced Drainage Systems, Inc. and subsidiaries (collectively referred to as “ADS” and the “Company”), incorporated in Delaware, designs, manufactures and markets high performance thermoplastic corrugated pipe and related water management products, primarily in North and South America and Europe. ADS’s broad product line includes corrugated high-density polyethylene (or “HDPE”) pipe, polypropylene (or “PP”) pipe and related water management products. The Company’s fiscal year begins on April 1 and ends on March 31. Unless otherwise noted, references to “year” pertain to our fiscal year. For example, 2020 refers to fiscal 2020, which is the period from April 1, 2019 to March 31, 2020. On July 31, 2019, the Company completed the Acquisition of Infiltrator Water Technologies. Infiltrator Water Technologies is a leading national provider of plastic leach field chambers and systems, septic tanks and accessories, primarily for use in residential applications. Infiltrator Water Technologies’ products are used in on-site septic wastewater treatment systems in the United States and Canada. See “Note 3. Acquisitions” for additional information on the Acquisition The Company is managed and reports results of operations in three reportable segments: Pipe, Infiltrator Water Technologies and International. The Company also reports the results of its Allied Products and all other business segments as Allied Products & Other. Principles of Consolidation - The consolidated financial statements include the Company, its wholly-owned subsidiaries, its majority owned subsidiaries, and variable interest entities (“VIEs”) of which the Company is the primary beneficiary. The Company uses the equity method of accounting for equity investments where it exercises significant influence but does not hold a controlling financial interest. Such investments are recorded in Other assets in the Consolidated Balance Sheets and the related equity in earnings from these investments are included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations. All intercompany balances and transactions have been eliminated in consolidation. Estimates - The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingencies and liabilities at the balance sheet date and the reported amounts of revenues and expenses during the reporting period. Significant estimates include, but are not limited to, purchase accounting for the Acquisition, the allowance for doubtful accounts, valuation of inventory, useful lives of property, plant and equipment and amortizing intangible assets, determination of the proper accounting for leases, valuation of equity method investments, goodwill, intangible assets and other long-lived assets for impairment, accounting for stock-based compensation and the ESOP, valuation of the redeemable convertible preferred stock, determination of allowances for sales returns, rebates and discounts, determination of the valuation allowance, if any, on deferred tax assets, and reserves for uncertain tax positions. Management’s estimates and assumptions are evaluated on an ongoing basis and are based on historical experience, current conditions and available information. Management believes the accounting estimates are appropriate and reasonably determined; however, due to the inherent uncertainties in making these estimates, actual results could differ from those estimates. Receivables and Allowance for Doubtful Accounts - Receivables include trade receivables, net of an allowance for doubtful accounts, and other miscellaneous receivables. Receivables at March 31, 2020 and 2019 are as follows: (Amounts in thousands) 2020 2019 Trade receivables, net $ 195,968 $ 170,887 Other miscellaneous receivables 4,060 16,104 Receivables, net $ 200,028 $ 186,991 As of March 31, 2020 and 2019, Other miscellaneous receivables includes insurance recoverables of approximately $3.2 million and $3.9 million, respectively, which has a corresponding liability recorded in Other accrued liabilities. Credit is extended to customers based on an evaluation of their financial condition and collateral is generally not required. The evaluation of the customer’s financial condition is performed to reduce the risk of loss. Accounts receivable are evaluated for collectability based on numerous factors, including the length of time individual receivables are past due, past transaction history with customers, their credit worthiness and the economic environment. This estimate is periodically adjusted when management becomes aware of a situation in which there is doubt the customer does not have the ability or intention to pay its financial obligations (e.g. bankruptcy filing). Inventories - Inventories are stated at the lower of cost or net realizable value. The Company’s inventories are maintained on the first-in, first-out (“FIFO”) method. Costs include the cost of acquiring materials, including in-bound freight from vendors and freight incurred for the transportation of raw materials, tooling or finished goods between the Company’s manufacturing plants and its distribution centers, direct and indirect labor, factory overhead and certain corporate overhead costs related to the production of inventory. The portion of fixed manufacturing overhead that relates to capacity in excess of our normal capacity is expensed in the period in which it is incurred and is not included in inventory. Net realizable value of inventory is established with consideration given to deterioration, obsolescence, and other factors. The Company periodically evaluates the carrying value of inventories and adjustments are made whenever necessary to reduce the carrying value to net realizable value. Property, Plant and Equipment and Depreciation Method - Property, plant and equipment are recorded at cost less accumulated depreciation, with the exception of assets acquired through acquisitions, which are initially recorded at fair value. Equipment acquired under finance lease is recorded at the present value of the future minimum lease payments. Depreciation is computed for financial reporting purposes using the straight-line method over the estimated useful lives of the related assets or the lease term, if shorter, as follows: Years Buildings and leasehold improvements 20 to 45 or the lease term if shorter Machinery and production equipment 3 to 18 Transportation equipment 3 to 12 Costs of additions and major improvements are capitalized, whereas maintenance and repairs that do not improve or extend the life of the asset are charged to expense as incurred. When assets are retired or disposed, the cost and related accumulated depreciation are removed from the asset accounts and any resulting gain or loss is reflected in Loss on disposal of assets and costs from exit and disposal activities in our Consolidated Statements of Operations. Construction in progress is also recorded at cost and includes capitalized interest, capitalized payroll costs and related costs such as taxes and other fringe benefits. Goodwill - The Company records acquisitions resulting in the consolidation of an enterprise using the acquisition method of accounting. Under this method, the Company records the assets acquired, including intangible assets that can be identified, and liabilities assumed based on their estimated fair values at the date of acquisition. The purchase price in excess of the fair value of the identifiable assets acquired and liabilities assumed is recorded as goodwill. Goodwill is reviewed annually for impairment as of March 31 or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not considered impaired and the Company is not required to perform further testing. If the carrying value of a reporting unit’s goodwill exceeds its fair value, then the Company would record an impairment loss equal to the difference. With respect to this testing, a reporting unit is a component of the Company for which discrete financial information is available and regularly reviewed by management. The fair value of goodwill is determined by considering both the income and market approach. Determining the fair value of a reporting unit is judgmental in nature and involves the use of significant estimates and assumptions. These estimates and assumptions include revenue growth rates and operating margins used to calculate projected future cash flows, risk-adjusted discount rates, future economic and market conditions, and determination of appropriate market comparison. The fair value estimates are based on assumptions management believes to be reasonable but are inherently uncertain. For the fiscal year ended March 31, 2020, the Company completed a quantitative fair value assessment for all reporting units and determined no impairment charge was required. For all other fiscal years presented, ADS completed a quantitative fair value assessment of the Canada reporting unit and determined no impairment charge was required. GAAP allows entities testing goodwill for impairment the option of performing a qualitative assessment before calculating the fair value of a reporting unit for the goodwill impairment test. If the qualitative assessment is performed, an entity is no longer required to calculate the fair value of a reporting unit unless the entity determines that, based on that assessment, it is not more likely than not that its fair value is less than its carrying amount. ADS applied the qualitative assessment to the former Domestic reporting unit for the annual impairment tests performed as of March 31, 2019 and 2018. The qualitative assessment indicated that no impairment charges were required for goodwill in the fiscal years ended March 31, 2019 and 2018. Intangible Assets Intangible Assets — Definite-Lived - Definite-lived intangible assets are amortized using the straight-line method or an accelerated method over their estimated useful lives and are tested for recoverability whenever events or changes in circumstances indicate that carrying amounts of the asset group may not be recoverable. Asset groups are established primarily by determining the lowest level of cash flows available. If the estimated undiscounted future cash flows are less than the carrying amounts of such assets, an impairment loss is recognized to the extent the fair value of the asset less any costs of disposition is less than the carrying amount of the asset. Determining the fair value of these assets is judgmental in nature and involves the use of significant estimates and assumptions. Intangible Assets — Indefinite-Lived - Indefinite-lived intangible assets are tested for impairment annually as of March 31 or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. Determining the fair value of these assets is judgmental in nature and involves the use of significant estimates and assumptions. The Company bases its fair value estimates on assumptions it believes to be reasonable, but that are inherently uncertain. To estimate the fair value of these indefinite-lived intangible assets, the Company uses an income approach, which utilizes a market derived rate of return to discount anticipated performance. An impairment loss is recognized when the estimated fair value of the intangible asset is less than the carrying value. ADS completed a quantitative fair value measurement of indefinite-lived trademarks as of March 31, 2020. The test indicated that the fair value of the indefinite-lived trademarks substantially exceeded the carrying value, indicating that no impairment existed. GAAP allows entities testing indefinite-lived intangible assets for impairment the option of performing a qualitative assessment before calculating the fair value of the indefinite-lived intangible assets for the impairment test. If the qualitative assessment is performed, an entity is no longer required to calculate the fair value of an indefinite-lived intangible assets unless the entity determines that, based on that assessment, it is more likely than not that its fair value is less than its carrying amount. ADS applied the qualitative assessment to specific trademarks for the annual impairment test s performed as of March 31, 2019 and 2018 . For the qualitative test, ADS assessed various assumptions, events and circumstances that would have affected the estimated fair value of the reporting unit as compared to its March 31, 2016 quantitative fair value measurement. The results of this assessment indicated that it is not more likely than not that the trademarks fair value is less than the reporting unit carrying value. The Company did no t incur any impairment charges for Intangible assets in the fiscal years ended March 31, 2019 and 2018 . Other Assets - Other assets include operating lease right of use assets, investments in unconsolidated affiliates accounted for under the equity method, capitalized software development costs, including cloud computing costs, deposits, central parts, and other miscellaneous assets. See “Note 6. Lease” for further information on the operating lease right of use assets. The Company capitalizes development costs for internal use software. Capitalization of software development costs begins in the application development stage and ends when the asset is placed into service. The Company amortizes such costs using the straight-line method over estimated useful lives of 2 to 10 years, which is included in General and administrative expense, Selling expense or Cost of goods sold within the Consolidated Statements of Operations depending on the nature of the asset and its intended use. Central parts represent spare production equipment items which are used to replace worn or broken production equipment parts and help reduce the risk of prolonged equipment outages. The cost of central parts is amortized on a straight-line basis over estimated useful lives of 3 to 10 years. The Company evaluates its investments in unconsolidated affiliates for impairment whenever events or changes in circumstances indicate that the carrying amount might not be recoverable and recognizes an impairment loss when a decline in value below carrying value is determined to be other-than-temporary. Under these circumstances, the Company would adjust the investment down to its estimated fair value, which then becomes its new carrying value. The impairment charge is included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations. Other assets as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Right of use assets - Operating leases $ 24,875 $ — Investments in unconsolidated affiliates 9,250 10,467 Capitalized software development costs, net 11,045 13,069 Deposits 3,842 2,985 Central parts 6,745 2,385 Other 13,383 8,034 Total other assets $ 69,140 $ 36,940 The following table sets forth amortization expense related to Other assets in each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Capitalized software development costs $ 3,116 $ 2,659 $ 2,156 Central parts 87 73 47 Other 85 1,419 1,688 Leases - The Company determines whether an arrangement contains a lease at inception by determining if the contract conveys the right to control the use of identified plant, property, and equipment for a period of time in exchange for consideration and other facts and circumstances as defined by ASC 842. For each lease which has an accounting lease term of greater than 12 months, the Company records the right-of-use asset and lease liability on the balance sheet. The accounting lease term includes cancellable and renewal periods which are reasonably assured. The lease liability is measured utilizing the incremental borrowing rate unless the Company can specifically determine the rate implicit in the lease. Leases are evaluated for appropriate classification as operating or financing at lease inception. For leases classified as finance leases at lease inception, the Company records a finance lease asset and lease financing obligation equal to the present value of the minimum lease payments. The finance lease right of use asset is recorded in Property, plant and equipment, net and amortized to its expected residual value at the end of the lease term using the straight-line method, and the lease financing obligation is amortized using the effective interest method over the lease term with the rental payments being allocated to principal and interest. For leases classified as operating leases, the Company records the operating lease right of use asset in other assets and operating lease obligation in other accrued liabilities and other liabilities. Operating lease rent expense over the useful life using the straight-line method. Foreign Currency Translation - Assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at the current rate of exchange on the last day of the reporting period. Revenues and expenses are translated at a monthly average exchange rate and equity transactions are translated using either the actual exchange rate on the day of the transaction or a monthly average historical exchange rate. The South American Joint Venture operates within Argentina, which on July 1, 2018, was identified for high inflationary accounting. The Company has determined the effect of a change in the exchange rate under high inflationary accounting does not have a material effect on the Company’s results in any annual period. For the fiscal years ended March 31, 2020 and 2019, the Company’s Accumulated other comprehensive loss (“AOCL”) consisted of foreign currency translation gains and losses. Net Sales - The Company generates revenue by selling pipe and related water management products primarily to distributors, retailers, buying groups and co-operative buying groups. Products are shipped predominately by the Company’s internal fleet, and the Company does not provide any additional revenue generating services after product delivery. Payment terms and conditions vary by contract. Revenue is recognized at the point in-time obligations under the terms of a contract with a customer are satisfied, which generally occurs upon the transfer of control of the promised goods. In substantially all of the Company’s contracts with customers, control is transferred to the customer upon delivery. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. Shipping Costs - The Company incurs shipping costs to deliver products to customers using an in-house fleet or common carrier. Typically shipping costs are prepaid and included in the product price; however, in some instances, the Company bills shipping costs to customers. Shipping costs are also incurred to physically move raw materials, tooling and products between manufacturing and distribution facilities. Shipping costs to deliver products to customers for the fiscal years ended March 31, 2020, 2019, and 2018 were $149.0 million, $131.3 million, and $120.7 million, respectively, and are included in Cost of goods sold. Shipping costs billed to customers were $7.9 million, $7.7 million, and $6.3 million during 2020, 2019 and 2018, respectively, and are included in Net sales. Stock-Based Compensation - See “Note 17. Stock-Based Compensation” for information about our stock-based compensation award programs and related accounting policies. Advertising - The Company expenses advertising costs as incurred. Advertising costs are recorded in Selling expenses in the Consolidated Statements of Operations. The total advertising costs were $4.9 million, $3.8 million, and $4.1 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively Self-Insurance - The Company is self-insured for short term disability and medical coverage it provides for substantially all eligible employees. The Company is self-insured for medical claims up to the individual and aggregate stop-loss coverage limits. The Company accrues for claims incurred but not reported based on an estimate of future claims related to events that occurred prior to the fiscal year end if it has not met the aggregate stop-loss coverage limit. Amounts expensed totaled $50.3 million, $42.4 million, and $41.3 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively, of which employees contributed $7.9 million, $6.7 million, and $5.9 million, respectively ADS is also self-insured for various other general insurance programs to the extent of the applicable deductible limits on the Company’s insurance coverage. These programs include primarily automobile, general liability and employment practices coverage with a deductible of $0.5 million per occurrence or claim incurred. Amounts expensed during the period, including an estimate for claims incurred but not reported at year end, were $2.5 million, $2.3 million, and $2.2 million, for the years ended March 31, 2020, 2019, and 2018, respectively. ADS is also self-insured for workers’ compensation insurance with stop-loss coverage for claims that exceed $0.3 million per incident up to the respective state statutory limits. Amounts expensed, including an estimate for claims incurred but not reported, were $3.0 million, $2.8 million, and $1.3 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively. Income Taxes - Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized and represent the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. They are measured using the enacted tax rates expected to apply to taxable income in the years in which the related temporary differences are expected to be recovered or settled. Valuation allowances are established against deferred tax assets when it is more likely than not that the realization of those deferred tax assets will not occur. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The deferred income tax provision represents the change during the reporting period in the deferred tax assets and deferred tax liabilities. Penalties and interest recorded on income taxes payable are recorded as part of Income tax expense. The Company determines whether an uncertain tax position is more likely than not to be sustained upon examination, including resolution of any related appeals or litigation process, based upon the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority. Fair Values - The fair value framework requires the categorization of assets and liabilities into three levels based upon assumptions (inputs) used to price the assets or liabilities. Level 1 provides the most reliable measure of fair value, whereas Level 3 generally requires significant management judgment. ADS’s policy for determining when transfers between levels have occurred is to use the actual date of the event or change in circumstances that caused the transfer. Concentrations of Risk - The Company has a large, active customer base of approximately twenty thousand customers with two customers, Ferguson Enterprises and Core and Main, each representing more than 10% of annual net sales. Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of Receivables. The Company provides its products to customers based on an evaluation of the customers’ financial condition, generally without requiring collateral. Exposure to losses on Receivables is principally dependent on each customer’s financial condition. The Company performs ongoing credit evaluations of its customers. The Company monitors the exposure for credit losses and maintains allowances for anticipated losses. Concentrations of credit risk with respect to Receivables are limited due to the large number of customers comprising the Company’s customer base and their dispersion across many different geographies. One customer, Ferguson Enterprises, accounted for approximately 18.2 % and 19.1 % of Receivables at March 31, 2020 and 2019 , respectively . Derivatives - The Company recognizes derivative instruments as either assets or liabilities and measure those instruments at fair value. ADS uses interest rate swaps, commodity options in the form of collars and swaps, and foreign currency forward contracts to manage various exposures to interest rate, commodity price, and exchange rate fluctuations. These instruments do not qualify for hedge accounting treatment. For the interest rate swap executed on June 28, 2017, gains and losses resulting from the difference between the spot rate and applicable base rate was recorded in Interest expense. For commodity options in the form of collars and swaps, and foreign currency forward contracts, gains and losses from contract settlements and changes in fair value of the derivative instruments are recognized in Derivative losses (gains) and other expense (income), net in the Consolidated Statements of Operations. The Company’s policy is to present all derivative balances on a gross basis. The Company also has forward purchase agreements in place with certain resin suppliers for virgin polyethylene resin. The agreements specify a fixed amount of virgin resin material to be purchased at a fixed price for a given period of time in quantities the Company will use in the normal course of business, and therefore, qualify as normal purchase contracts. The cost of such resin is recognized in Cost of goods sold in the Consolidated Statements of Operations. Recent Accounting Pronouncements Recently Adopted Accounting Guidance Leases - In February 2016, the Financial Accounting Standards Board (the “FASB”) issued an accounting standard update (“ASU”) which amends the guidance for leases (“ASC 842”). This standard contains principles that will require an entity to recognize most leases on the balance sheet by recording a right-of-use asset and a lease liability, unless the lease is a short-term lease that has an accounting lease term of twelve months or less. The standard also contains other changes to the current lease guidance that may result in changes to how entities determine which contractual arrangements qualify as a lease, the accounting for executory costs, such as property taxes and insurance, as well as which lease origination costs will be capitalizable. In July 2018, the FASB amended ASC 842 to provide another transition method, allowing a cumulative effect adjustment to the opening balance of retained earnings during the period of adoption. The Company adopted these standards effective April 1, 2019 using the transition method in the July 2018 ASU which does not require adjustments to comparative periods or require modified disclosures for those periods and includes transition relief practical expedients. See “Note 6. Leases” for further information on the adoption of the new lease ASUs. Hedge Accounting - In August 2017, the FASB issued an ASU which expanded an entity’s ability to apply hedge accounting for non-financial and financial risk components and provided a simplified approach for fair value hedging of interest rate risk. The standard also refined how entities assess hedge effectiveness. The Company adopted this standard effective April 1, 2019. The new standard did not have an impact on the Consolidated Financial Statements. Recent Accounting Guidance Not Yet Adopted Measurement of Credit Losses - In June 2016, the FASB issued an ASU which provides amended guidance on the measurement of credit losses on financial instruments, including trade receivables. This standard requires the use of an impairment model referred to as the current expected credit loss model. This standard is effective for fiscal years beginning after December 15, 2019, including interim periods within those years, and early adoption is permitted for fiscal years beginning after December 15, 2018. The Company will adopt this standard effective April 1, 2020. The Company’s adoption of the standard will not have a material impact on the Company’s Consolidated Financial Statements. Reference Rate Reform - In March 2020, the FASB issued an ASU that provides optional expedients and exceptions related to financial reporting impacts related to the expected market transition from LIBOR to another reference rates. The amendments are effective on March 12, 2020 and an entity may elect to adopt prospectively through December 31, 2022. The Company is currently evaluating the impact of this standard on the Consolidated Financial Statements. Income Taxes – In December 2019, the FASB issued an ASU to simplify the accounting for income taxes by removing certain exceptions to the general principles in ASC 740, and improve the comparability of financial statements. The amendments in this ASU are effective for fiscal years beginning after December 15, 2020, and early adoption is permitted. The Company is currently evaluating the impact of this standard on the Consolidated Financial Statements. Except for the pronouncements described above, there have been no new accounting pronouncements issued or adopted since the filing of the fiscal 2019 Form 10-K that have significance, or potential significance, to the Consolidated Financial Statements.

Loss on Disposal of Assets and

Loss on Disposal of Assets and Costs from Exit and Disposal Activities	12 Months Ended
	Mar. 31, 2020
Discontinued Operations And Disposal Groups [Abstract]
Loss on Disposal of Assets and Costs from Exit and Disposal Activities	2. LOSS ON DISPOSAL OF ASSETS AND COSTS FROM EXIT AND DISPOSAL ACTIVITIES In fiscal 2018, the Company initiated restructuring activities (the “2018 Restructuring Plan”), which concluded during fiscal 2019, including closing underutilized manufacturing facilities, reducing headcount, optimizing product offerings and eliminating nonessential costs, designed to improve the Company’s cost structure. The Company closed one and four manufacturing facilities in the fiscal years ended March 31, 2019 and 2018, respectively. The Company does not currently have a specified restructuring plan. The following table summarizes the activity included in Loss on disposal of assets and costs from exit and disposal activities recorded during the fiscal years ended March 31, 2020, 2019, and 2018: The following table summarizes the activity included in loss on disposal of assets and costs from exit and disposal activities recorded during the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Accelerated depreciation $ — $ 430 $ 3,759 Plant severance — 131 2,041 Headcount reduction — 306 4,133 Product optimization — 283 1,351 Other restructuring activities — 475 159 Total 2018 Restructuring Plan activities $ — $ 1,625 $ 11,443 Acquisition related severance and other costs 2,557 $ — $ — Loss on other disposals and partial disposals of property, plant and equipment 2,781 2,022 3,560 Total loss on disposal of assets and costs from exit and disposal activities $ 5,338 $ 3,647 $ 15,003 Approximately $1.2 million and $0.4 million for fiscal year ended March 31, 2019, related to the Pipe and International reportable segment, respectively, and $11.0 million and $0.4 million for the fiscal year ended March 31, 2018 of the Total 2018 Restructuring Plan activities related to the Pipe and International reporting segment, respectively. All of the Company’s restructuring liability related to the Pipe reportable segment. A reconciliation of the beginning and ending amounts of restructuring liability related to the 2018 Restructuring Plan for the fiscal years ended March 31, 2020 and 2019 (Amounts in thousands) 2020 2019 Balance at beginning of year $ 1,696 $ 3,901 Expenses — 1,625 Non-cash expenses — (713 ) Payments (1,122 ) (3,117 ) Balance at end of year $ 574 $ 1,696 The Company had $0.1 million and $0.6 million of long-term severance liability related to the restructuring activities recorded in Other liabilities in the Consolidated Balance Sheet as of March 31, 2020 and March 31, 2019, respectively. Periodically, the Company will dispose of equipment, including equipment accounted for as finance leases. The net loss on the disposition of the equipment was $2.8 million, $2.0 million, and $3.6 million during fiscal 2020, 2019 and 2018, respectively.

Revenue Recognition

Revenue Recognition	12 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Revenue Recognition	3. REVENUE RECOGNITION On April 1, 2018, the Company adopted ASC 606, Revenue from Contracts with Customers (“ASC 606”), and all related amendments using the modified retrospective transition method. The adoption of ASC 606 did not impact the opening retained earnings balance or cause a material shift in the amount or timing of revenue recognition. Results for reporting periods beginning after April 1, 2018 are presented under ASC 606, while prior period amounts were not adjusted and continue to be reported in a consistent manner with historical accounting policies. The Company generates revenue by selling pipe and related water management products primarily to distributors, retailers, buying groups and co-operative buying groups. Products are shipped predominately by the Company’s internal fleet, and the Company does not provide any additional revenue generating services after product delivery. Payment terms and conditions vary by contract. Revenue is recognized at the point in-time obligations under the terms of a contract with a customer are satisfied, which generally occurs upon the transfer of control of the promised goods. In substantially all of the Company’s contracts with customers, control is transferred to the customer upon delivery. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. Revenue is presented in the Consolidated Statements of Operations net of allowances for returns, rebates, discounts, and taxes collected concurrently with revenue-producing activities. The Company disaggregates net sales by Domestic, International and Infiltrator Water Technologies and further disaggregates Domestic and International by product type, consistent with its reportable segment disclosure. This disaggregation level best depicts how the nature, amount, timing and uncertainty of revenue and cash flows are affected by economic factors. Refer to “Note 21. Business Segments Information” for the Company’s disaggregation of Net sales by reportable segment. Significant Judgments - The Company’s performance obligation under contracts with customers is to sell and deliver pipe and related water management products. The Company’s contracts with customers may contain multiple performance obligations by promising to deliver multiple products to the customer. For these contracts, the Company accounts for individual performance obligations separately if they are distinct. The transaction price is allocated to the separate performance obligations on a relative standalone selling price basis. The Company’s products are generally sold with a right of return, and the Company may provide credits or incentives, which are accounted for as variable consideration when estimating the amount of revenue to recognize. Variable consideration is estimated at contract inception and updated at the end of each reporting period as additional information becomes available and only to the extent that it is probable that a significant reversal of any incremental revenue will not occur. Contract Balances - The Company recognizes a contract asset representing the Company’s right to recover products upon the receipt of returned products and a contract liability for the customer refund. The adoption of this standard resulted in the Company recording a contract asset for estimated inventory returns. On April 1, 2018, the estimated inventory returns resulted in a $0.6 million decrease in Receivables, net and a $0.6 million increase in Other current assets on the Company’s Consolidated Balance Sheets. March 31, 2020 April 1, 2019 (In thousands) Contract asset - product returns $ 594 $ 646 Refund liability 1,458 1,372 Practical Expedients and Exemptions - The Company expenses incremental costs to obtain a contract (e.g. sales commissions) when incurred as the amortization period would have been one year or less. These costs are recorded within selling expenses on the Consolidated Statements of Operations. The Company elected the accounting policy election permitted by ASC 606 to account for shipping and handling costs as activities to fulfill the promise to transfer the goods when these activities are performed after a customer obtains control of the goods. The Company elected the accounting policy to exclude from the transaction price all sales taxes that are assessed by a governmental authority and that are imposed on and concurrent with a specific revenue-producing transaction and collected by the Company from a customer, for example, sales, use, value added, and some excise taxes. Further, the Company does not disclose the value of unsatisfied performance obligations for contracts with an original expected length of one year or less.

Acquisitions

Acquisitions	12 Months Ended
	Mar. 31, 2020
Business Combinations [Abstract]
Acquisitions	4 . ACQUISITIONS Fiscal 2020 Acquisition of Infiltrator Water Technologies On July 31, 2019 (the “Closing Date”), the Company completed its Acquisition of Infiltrator Water Technologies pursuant to an Agreement and Plan of Merger (the “Merger Agreement”) dated July 31, 2019. Infiltrator Water Technologies manufactures and sells wastewater systems for homes and provides drainage chambers for septic and storm water management. The total fair value of consideration transferred was $1,147.2 million. The Merger Agreement was funded through the Bridge Loan Facility as further described in “Note 13. Debt”. The results of operations of Infiltrator Water Technologies are included in the Consolidated Statements of Operations after July 31, 2019. The following table summarizes the consideration transferred and the preliminary purchase price allocation of the assets acquired and liabilities assumed. The Company’s estimates and assumptions are subject to change during the measurement period. The measurement period ends on July 31, 2020. Any changes to the Company’s estimates or assumptions may result in material changes from the preliminary purchase price allocations. (Amounts in thousands) Initial Amount Adjustments to Purchase Price Adjustments to Property, Plant and Equipment Adjustments to Intangible Assets Tax Adjustments Updated Amount Cash $ 57,375 $ — $ — $ — $ — $ 57,375 Total current assets, excluding cash 75,847 — — — — 75,847 Property, plant and equipment 98,860 — (6,575 ) — — 92,285 Goodwill 567,034 704 6,575 (100,000 ) 21,528 495,841 Intangible assets, net 475,000 — — 100,000 — 575,000 Other assets 14,366 — — — — 14,366 Total current liabilities (22,756 ) — — — 931 (21,825 ) Deferred tax liabilities (109,926 ) — — — (22,459 ) (132,385 ) Other liabilities (9,274 ) — — — — (9,274 ) Total fair value of consideration transferred $ 1,146,526 $ 704 $ — $ — $ — $ 1,147,230 The fair value of consideration transferred includes $6.0 million of Infiltrator Water Technologies payable to the Company and $6.6 million of Infiltrator Water Technologies receivable due from the Company. The goodwill of $495.8 million represents the excess of consideration transferred over the fair value of assets acquired and liabilities assumed and is attributable to expected revenue synergies, as well as operating efficiencies and cost savings. The goodwill is not deductible for tax purposes and is assigned to the Infiltrator Water Technologies segment. Of the $132.4 million of preliminary purchase price allocated to deferred tax liabilities, $82.3 million related to the step up of GAAP basis for fair market valuations, while the remaining $50.1 million were acquired deferred tax liabilities. Of the total $82.3 million, $80.2 million was attributed to intangible assets. See “Note 18. Income Taxes” for additional information. The purchase price excludes transaction costs. During the fiscal year ended March 31, 2020, the Company incurred $22.9 million of transaction costs related to the Acquisition such as legal, accounting, valuation and other professional services. The Company estimates approximately $7.3 million of transaction costs are not deductible for tax purposes. These costs are included in general and administrative expenses in the Consolidated Statements of Operations and Consolidated Statements of Comprehensive Income. The identifiable intangible assets recorded in connection with the closing of the Acquisition are based on valuations including customer relationships, patents and developed technology, and tradename and trademarks totaling $575.0 million. Customer relationships are amortized using an accelerated method over an estimated useful life of 20 years. Patents and developed technology and tradename and trademarks are on a straight-line basis over the respective useful lives of 10 and 20 years. (Amounts in thousands) Preliminary fair value Estimated useful lives Customer relationships $ 360,000 20 years Patents and developed technology 150,000 10 years Tradename and trademarks 65,000 20 years Total identifiable intangible assets $ 575,000 The net sales to external customers of Infiltrator Water Technologies since the acquisition are included in the Consolidated Statements of Operations for the fiscal year ended March 31, 2020 was $169.3 million. The income before taxes of Infiltrator Water Technologies since the acquisition are included in the Consolidated Statements of Operations for the fiscal year ended March 31, 2020 was $8.2 million The unaudited pro forma information for the fiscal year ended March 31, 2020 presented below includes the effects of the Acquisition as if it had been consummated as of April 1, 2017, with adjustments to give effect to pro forma events that are directly attributable to the Acquisition. Adjustments include those related to the amortization of acquired intangible assets, increases in interest expense due to additional borrowings incurred to finance the Acquisition, transaction costs, the elimination of transactions between the Company and Infiltrator Water Technologies and the estimated tax impacts thereof. The unaudited pro forma information does not reflect any operating efficiency or potential cost savings that could result from the consolidation of Infiltrator Water Technologies. Accordingly, the unaudited pro forma information is presented for informational purposes only and is not necessarily indicative of the actual results of the combined company if the Acquisition had occurred at the beginning of the period presented, nor is it indicative of the future results of operations. (Amounts in thousands) 2020 2019 2018 Net sales $ 1,760,208 $ 1,608,450 $ 1,520,571 Net income (loss) attributable to ADS (145,244 ) 27,411 (33,606 ) Fiscal 2019 Acquisition of N oncontrolling interest in BaySaver BaySaver Technologies LLC (“BaySaver”) was a joint venture that was established to produce and distribute water quality filters and separators used in the removal of sediment and pollution from storm water. During the third quarter of fiscal 2019, ADS purchased the remaining 35% ownership interest in BaySaver for a purchase price of $8.8 million. The purchase of the remaining 35% ownership interest was reflected as a reduction in the Redeemable noncontrolling interest in subsidiary in the Consolidated Balance Sheets and as a financing activity in the Consolidated Statement of Cash Flows. Additionally, resulting from this transaction, the Company recorded a $0.4 million non-cash adjustment to deferred taxes. BaySaver is now a wholly-owned subsidiary of ADS. Fiscal 2018 Acquisition of DURASLOT, Inc. On August 1, 2017, ADS acquired DURASLOT, Inc., a manufacturer of linear surface drains, for $2.3 million. The acquisition included approximately $2.1 million of tax-deductible goodwill. The acquisition of DURASLOT, Inc. is included in Other investing activities on the Consolidated Statement of Cash Flows.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Property, Plant and Equipment	5 . PROPERTY, PLANT AND EQUIPMENT Property, plant and equipment, net as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Land, buildings and improvements $ 253,379 $ 199,810 Machinery and production equipment 631,932 560,858 Transportation equipment 208,037 221,721 Construction in progress 19,925 19,749 Total cost 1,113,273 1,002,138 Less: accumulated depreciation (631,893 ) (603,247 ) Property, plant and equipment, net $ 481,380 $ 398,891 The following table sets forth depreciation expense related to Property, plant and equipment in each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Depreciation expense (inclusive of leased assets depreciation) (1) $ 64,642 $ 59,869 $ 63,044 (1) Depreciation expense does not include accelerated depreciation expense from the 2018 Restructuring plan. See “Note 2. Loss on Disposal of Assets and Costs from Exit and Disposal Activities” for additional discussion.

Leases

Leases	12 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Lessee	6 . LEASES ASC 842 Adoption - The Company adopted the provisions of ASC 842 beginning on April 1, 2019 using the transition methodology in ASC 842 which does not require adjustments to comparative periods or require modified disclosures. The Company elected the transition relief practical expedient package as described in ASC 842-10-65-1. ASC 842 provides lessees with the option of electing an accounting policy, by class of underlying asset, in which the lessee may choose not to separate nonlease components from lease components. The Company elected this practical expedient for leases of certain classes of equipment, including forklifts and fleet tractors and trailers. The Company also elected the accounting policy to not recognize the right-of-use asset and lease liability for leases with an accounting lease term of twelve months or less (“Short-term leases”). The adoption of ASC 842 resulted in the recording of $13.3 million of additional lease liabilities and right-of-use assets to the beginning balance of the Company’s Consolidated Balance Sheet. Infiltrator Water Technologies adopted ASC 842 on July 31, 2019 using the same methodology and policy elections taken by the Company on April 1, 2019. The Infiltrator Water Technologies adoption of ASC 842 resulted in the recording of $11.2 million of additional lease liabilities and corresponding right-of-use assets to the beginning balance of the Company’s Consolidated Balance Sheet. At the date of adoption, ASC 842 did not have an impact on the Company’s Consolidated Statement of Operations and Consolidated Statement of Cash Flows. Nature of the Company’s Leases - The Company has operating and finance leases for plants, yards, corporate offices, tractors, trailers and other equipment. The Company’s leases have remaining terms of less than one year to 30 years. A portion of the Company’s real estate leases include an option to extend the leases for up to 5 years. The Company has included renewal options which are reasonably certain to be exercised in its right-of-use assets and lease liabilities. The Company’s lease payments are generally fixed. Certain equipment leases contain residual value guarantees that create a contingent obligation on the part of the Company to compensate the lessor if the leased asset cannot be sold for an amount in excess of a specified minimum value at the conclusion of the lease term. The calculation is based on the original cost of the transportation equipment, less lease payments made, compared to a percentage of the transportation equipment’s fair market value at the time of sale. All leased units covered by this guarantee have been classified as finance leases and a corresponding finance lease obligation was recorded. Therefore, no contingent obligation is needed. For all leases with an initial expected term of more than 12 months, the Company recorded, at the adoption date of ASC 842 or lease commencement date for leases entered into after the adoption date, a lease liability, which is the lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The Company will utilize its collateralized incremental borrowing rate commensurate to the lease term as the discount rate for its leases, unless the Company can specifically determine the lessor’s implicit rate. The incremental borrowing rate for each lease is determined based on the Company’s credit rating, adjusted for the impacts of collateral, and the lease term. Lease Cost - The components of lease cost for the year ended March 31, 2020 was: (Amounts in thousands) Income Statement Classification 2020 Operating lease cost Operating lease cost Cost of goods sold $ 5,548 Operating lease cost General and administrative 1,204 Short-term lease cost Cost of goods sold 2,393 Total operating lease cost $ 9,145 Finance lease cost Amortization of right-of-use assets Cost of goods sold 17,059 Amortization of right-of-use assets General and administrative 2,543 Interest on lease liabilities Interest expense 4,344 Total finance lease cost $ 23,946 Supplemental cash flow information related to leases for the fiscal year ended March 31, 2020 was as follows: (Amounts in thousands) 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 6,572 Operating cash flows from finance leases 4,675 Financing cash flows from finance leases 27,119 Right-of-use assets obtained in exchange for lease obligations: Operating leases 10,529 Finance leases (a) 5,078 (a) The Company acquired $27.6 million and $26.8 million of property, plant and equipment under finance leases in the fiscal years ended March 31, 2019 and March 31, 2018, respectively. Supplemental balance sheet information related to leases as of March 31, 2020 was as follows: (Amounts in thousands) Balance Sheet Classification 2020 Operating leases Right-of-use assets Other assets $ 24,875 Current lease liabilities Other accrued liabilities 7,757 Non-current lease liabilities Other liabilities 17,173 Total operating lease liabilities $ 24,930 Finance leases Right-of-use assets Property, plant and equipment 90,756 Current lease liabilities Current maturities of finance lease obligations 20,382 Non-current lease liabilities Long-term finance lease obligations 44,501 Total finance lease liabilities $ 64,883 Weighted average lease term Operating leases 6.97 Finance leases 10.72 Weighted average discount rate Operating leases 3.57 % Finance leases 5.36 % The following is a schedule by year of future minimum lease payments on a rolling twelve-month basis under operating and finance leases and the present value of the net minimum lease payments as of March 31, 2020: (Amounts in thousands) Operating Leases Finance Leases Year 1 $ 8,511 $ 23,492 Year 2 5,717 19,478 Year 3 3,839 13,182 Year 4 2,768 8,355 Year 5 2,041 4,736 Thereafter 6,075 4,722 Total minimum lease payments $ 28,951 $ 73,965 Less: amount representing interest 4,021 9,082 Present value of net minimum lease payments $ 24,930 $ 64,883 Disclosures Related to Periods Prior to the Adoption of ASC 842 – Leased assets included in Property, plant and equipment as of the fiscal year ended March 31, 2019 consisted of the following: (Amounts in thousands) 2019 Buildings and improvements $ 5,357 Machinery and equipment 220,279 Total cost 225,636 Less: accumulated depreciation (114,856 ) Leased assets in Property, plant and equipment, net $ 110,780 The following sets forth the interest and depreciation expense related to capital leases recorded in each fiscal year ended March 31: (Amounts in thousands) 2019 2018 Lease interest expense $ 5,215 $ 4,086 Depreciation of leased assets 19,155 18,511 As of March 31, 2019, total contractual obligations for capital and operating leases were as follows: (Amounts in thousands) Operating Leases Finance Leases Year 1 $ 4,159 $ 26,604 Year 2 2,924 22,507 Year 3 1,814 18,064 Year 4 690 11,721 Year 5 325 7,143 Thereafter 2,236 8,198 Total minimum lease payments $ 12,148 $ 94,237 Less: amount representing interest — 9,565 Present value of net minimum lease payments $ 12,148 $ 84,672

Inventories

Inventories	12 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Inventories	7 . INVENTORIES Inventories as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Raw materials $ 66,524 $ 47,910 Finished goods 215,874 216,630 Total Inventories $ 282,398 $ 264,540 The Company had no work-in-process inventories as of March 31, 2020 and 2019. During fiscal years ended March 31, 2020 and 2019, the Company incurred production-related general and administrative costs included in the cost of finished goods inventory of $38.8 million and $29.4 million, respectively, of which $8.6 million and $8.2 million remained in inventory at March 31, 2020 and 2019, respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Mar. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	8 . GOODWILL AND INTANGIBLE ASSETS Goodwill - The carrying amount of goodwill by reportable segment is as follows: As Previously Reported (Amounts in thousands) Domestic International Pipe Infiltrator Water Technologies Allied Products & Other Total Balance at March 31, 2018 $ 92,105 $ 10,912 $ — $ — $ — $ 103,017 Currency translation — (379 ) — — — (379 ) Balance at March 31, 2019 $ 92,105 $ 10,533 $ — $ — $ — $ 102,638 Reallocation due to change in segments (92,105 ) — 57,663 — 34,442 — Acquisition — — — 495,841 — 495,841 Currency translation — (660 ) — — — (660 ) Balance at March 31, 2020 $ — $ 9,873 $ 57,663 $ 495,841 $ 34,442 $ 597,819 Intangible Assets – Intangible assets as of March 31, 2020 and 2019 consisted of the following: 2020 2019 (Amounts in thousands) Gross Intangible Accumulated Amortization Net Intangible Gross Intangible Accumulated Amortization Net Intangible Definite-lived intangible assets Developed technology $ 177,579 $ (32,437 ) $ 145,142 $ 27,580 $ (19,922 ) $ 7,658 Customer relationships 377,742 (47,051 ) 330,691 29,851 (23,000 ) 6,851 Patents 8,951 (6,419 ) 2,532 8,313 (5,561 ) 2,752 Non-compete and other contractual agreements — — — 155 (138 ) 17 Trademarks and tradenames 69,847 (4,736 ) 65,111 15,978 (7,968 ) 8,010 Total definite lived intangible assets 634,119 (90,643 ) 543,476 81,877 (56,589 ) 25,288 Indefinite-lived intangible assets (a) Trademarks 11,862 — 11,862 11,889 — 11,889 Total Intangible assets $ 645,981 $ (90,643 ) $ 555,338 $ 93,766 $ (56,589 ) $ 37,177 (a) Indefinite-lived intangible assets decreased as a result of foreign currency translation. The gross intangible asset value of developed technology, customer relationships and trademarks and tradenames increased as a result of the Acquisition. See “Note 4. Acquisitions” for additional information. The following table presents the amortization expense and weighted average amortization period for definite-lived intangible assets at March 31, 2020: Amortization expense (in thousands) 2020 2019 2018 Weighted Average Amortization Period (in years) Developed technology $ 12,517 $ 2,517 $ 2,517 10.0 Customer relationships 36,093 3,546 3,633 19.8 Patents 522 546 591 12.0 Non-compete and other contractual agreements 22 22 104 — Trademarks and tradenames 7,856 1,249 1,223 19.6 The following table presents the future intangible asset amortization expense based on existing intangible assets at March 31, 2020: Fiscal Year (Amounts in thousands) 2021 2022 2023 2024 2025 Thereafter Total Amortization expense $ 71,705 $ 61,305 $ 52,328 $ 48,200 $ 44,872 $ 265,066 $ 543,476

Fair Value Measurement

Fair Value Measurement	12 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurement	9 . FAIR VALUE MEASUREMENT When applying fair value principles in the valuation of assets and liabilities, the Company is required to maximize the use of quoted market prices and minimize the use of unobservable inputs. The Company has not changed its valuation techniques used in measuring the fair value of any financial assets or liabilities during the fiscal years presented. The fair value estimates take into consideration the credit risk of both the Company and its counterparties. When active market quotes are not available for financial assets and liabilities, ADS uses industry standard valuation models. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs including credit risk, interest rate curves, foreign currency rates and forward and spot prices for currencies. In circumstances where market-based observable inputs are not available, management judgment is used to develop assumptions to estimate fair value. Generally, the fair value of our Level 3 instruments is estimated as the net present value of expected future cash flows based on internal and external inputs. Recurring Fair Value Measurements The assets, liabilities and mezzanine equity carried at fair value as of the fiscal years ended March 31 were as follows: March 31, 2020 (Amounts in thousands) Total Level 1 Level 2 Level 3 Assets: Derivative assets — diesel fuel contracts $ 36 $ — $ 36 $ — Total assets at fair value on a recurring basis $ 36 $ — $ 36 $ — Liabilities: Derivative liability - diesel fuel contracts $ 2,228 $ — $ 2,228 $ — Contingent consideration for acquisitions (a) 60 — — 60 Total liabilities at fair value on a recurring basis $ 2,288 $ — $ 2,228 $ 60 March 31, 2019 (Amounts in thousands) Total Level 1 Level 2 Level 3 Assets: Derivative assets — diesel fuel contracts $ 189 $ — $ 189 $ — Interest rate swaps 1,088 — 1,088 — Total assets at fair value on a recurring basis $ 1,277 $ — $ 1,277 $ — Liabilities: Derivative liability - diesel fuel contracts $ 283 $ — $ 283 $ — Foreign exchange forward contracts 60 — 60 — Contingent consideration for acquisitions 203 — — 203 Total liabilities at fair value on a recurring basis $ 546 $ — $ 343 $ 203 (a) The fair value of the contingent consideration for acquisitions is based on management’s estimate of contractual payments based on future product certifications obtained. The contingent consideration for acquisitions are recorded at their fair value based on a discounted cash flow valuation technique. The Company’s unobservable input is the weighted average cost of capital (“WACC”) which represents discount rates or rates of return estimates and assumptions that the Company believes would be used by market participants when valuing these liabilities. The Company’s weighted average cost of capital was approximately 9.5% as of March 31, 2020 and 2019. Changes in the fair value of recurring fair value measurements using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2020 and 2019 were as follows: Contingent consideration Balance at March 31, 2018 $ 578 Asset acquisition $ 40 Change in fair value (6 ) Payments of contingent consideration liability (409 ) Balance at March 31, 2019 $ 203 Payments of contingent consideration liability (143 ) Balance at March 31, 2020 $ 60 There were no transfers in or out of Level 3 for the fiscal years ended March 31, 2020 and 2019. Valuation of Contingent Consideration for Acquisitions - The method used to price these liabilities is considered Level 3, due to the subjective nature of the unobservable inputs used to determine the fair value. Valuation of Debt - The carrying amounts of current financial assets and liabilities approximate fair value because of the immediate or short-term maturity of these items, or in the case of derivative instruments, because they are recorded at fair value. The carrying and fair value of the Company’s Senior Notes (discussed in “Note 13. Debt”) were $350.0 million and $315.0 million, respectively, as of March 31, 2020 and $100.0 million and $98.9 million, respectively, at March 31, 2019. The fair value of the Senior Notes was determined based on a comparison of the interest rate and terms of such borrowings to the rates and terms of similar debt available for the period. The Company believes the carrying amount on the remaining long-term debt, including the Secured Bank Loans, is not materially different from its fair value as the interest rates and terms of the borrowings are similar to currently available borrowings. The categorization of the framework used to evaluate this debt is considered Level 2.

Investment in Affiliates

Investment in Affiliates	12 Months Ended
	Mar. 31, 2020
Unconsolidated Affiliates [Member]
Investment in Affiliates	1 1 . INVESTMENT IN UNCONSOLIDATED AFFILIATES The Company participates in an unconsolidated joint venture, South American Joint Venture, which is 50% owned by the Company’s wholly-owned subsidiary ADS Chile. Prior to April 2018, the Company participated in an unconsolidated joint venture, Tigre-ADS USA, Inc. (“Tigre-ADS USA”), which was 49% owned by the Company’s wholly-owned subsidiary ADS Ventures, Inc. South American Joint Venture - The Company’s investment in this unconsolidated joint venture was formed for the purpose of expanding upon the growth of manufacturing and selling HDPE corrugated pipe in the South American market via the joint venture partner’s local presence and expertise throughout the region. The Company has concluded that it is appropriate to account for this investment using the equity method, whereby the Company’s share of the income or loss of the joint venture is reported in the Consolidated Statements of Operations under Equity in net loss (income) of unconsolidated affiliates and the Company’s investment in the joint venture is included in Other assets in the Consolidated Balance Sheets. The Company is not required to consolidate the South American Joint Venture as it is not the primary beneficiary, although the Company does hold significant variable interests in the South American Joint Venture through the equity investment and debt guarantee. In order to improve the South American Joint Venture’s working capital position and allow it to reallocate capital resources to business growth, the Company and the joint venture partner each contributed equal amounts of outstanding receivables owed to them from the South American Joint Venture in exchange for incremental ownership interest in the South American Joint Venture in December 2017. The Company and the joint venture partner continue to maintain a 50% ownership interest in the South American Joint Venture following the contribution. As a result of the transaction the Company contributed receivables of approximately $5.8 million net of a $3.0 million allowance for doubtful accounts and recorded an additional investment in the South American Joint Venture at the fair value of $4.7 million and a $1.9 million gain on the book value of the receivables. The investment is recorded within Other assets on the Company’s Consolidated Balance Sheets and the gain is recorded within Equity in net (income) loss of unconsolidated affiliates on the Company’s Consolidated Statements of Operations. Past impairment charges have resulted in a basis difference between the cost of the investment and the amount of underlying equity in net assets of the South American Joint Venture of $3.7 million and $4.0 million as of March 31, 2020 and 2019, respectively. The basis difference will be amortized over the estimated remaining useful life of the underlying property, plant and equipment, 7 years. The Company recognized $0.3 million, $0.4 million and $0.5 million of amortization of the basis difference in fiscal 2020, 2019 and 2018, respectively. The impairment charge is included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations. Tigre-ADS USA - The former joint venture was established to manufacture and sell PVC fittings for waterworks, plumbing, and HVAC applications primarily in the United States and Canadian markets. The joint venture represent ed a continuation of the activities of Tigre-ADS USA through its Janesville, Wisconsin manufacturing facility. The Company was not required to consolidate Tigre-ADS USA as it was not the primary beneficiary, although the Company d id hold a significant variable interest in Tigre-ADS USA through the equity investment. In April 2018, the Company and the joint venture partner agreed to exchange the Company’s shares of Tigre-ADS USA for a release from the existing debt guarantees. Following the exchange, the Company no longer has an interest in Tigre-ADS USA. As a result of the agreement, the Company determined there was an other-than-temporary decline in the fair value of its investment in Tigre-ADS USA. Accordingly, the Company recorded an impairment charge of $0.3 million, reducing the carrying value of the investment to its fair value. The impairment charge is included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations.
Subsidiaries [Member]
Investment in Affiliates	10 . INVESTMENT IN CONSOLIDATED AFFILIATES ADS participates in one consolidated joint venture, ADS Mexicana, which is 51% owned by the Company’s wholly-owned subsidiary ADS Worldwide, Inc. The equity owned by the Company’s joint venture partner is shown as Noncontrolling interest in subsidiaries in the Consolidated Balance Sheets and the joint venture partner’s portion of net income is shown as Net income attributable to noncontrolling interest in the Consolidated Statements of Operations. ADS participated in an additional joint venture, BaySaver. In the third quarter of fiscal 2019, the Company acquired the noncontrolling interest in BaySaver. As a result, BaySaver is a wholly-owned subsidiary of the Company after the acquisition. Prior to the acquisition, the equity owned by the Company’s joint venture partner was shown as Redeemable noncontrolling interest in subsidiaries in the Consolidated Balance Sheets and the joint venture partner’s portion of net income is shown as Net income attributable to noncontrolling interest in the Consolidated Statements of Operations. ADS Mexicana - ADS participates in joint ventures for the purpose of expanding upon the growth of manufacturing and selling HDPE corrugated pipe and PVC conduit in emerging markets. ADS invested in ADS Mexicana for the purpose of expanding upon our growth of manufacturing and selling ADS licensed HDPE corrugated pipe and related products in the Mexican and Central American markets via the joint venture partner’s local presence and expertise throughout the region. The Company owns a 51% equity interest in ADS Mexicana. The Company executed a Technology, Patents and Trademarks Sub-License Agreement and a Distribution Agreement with ADS Mexicana that provides ADS Mexicana with the rights to manufacture and sell ADS licensed products in Mexico and Central America. The Company has concluded that it holds a variable interest in and is the primary beneficiary of ADS Mexicana based on the power to direct the most significant activities of ADS Mexicana and the obligation to absorb losses and the right to receive benefits that could be significant to ADS Mexicana. As the primary beneficiary, the Company is required to consolidate the assets and liabilities of ADS Mexicana. The table below includes the assets and liabilities of ADS Mexicana that are consolidated as of March 31, 2020 and 2019. The balances exclude intercompany transactions that are eliminated upon consolidation. (Amounts in thousands) 2020 2019 Assets Current assets $ 18,357 $ 18,683 Property, plant and equipment, net 12,438 17,054 Other noncurrent assets 1,317 1,396 Total assets $ 32,112 $ 37,133 Liabilities Current liabilities $ 6,350 $ 6,581 Noncurrent liabilities 1,131 1,264 Total liabilities $ 7,481 $ 7,845

Related Party Transactions

Related Party Transactions	12 Months Ended
	Mar. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	12. RELATED PARTY TRANSACTIONS ADS Mexicana - ADS conducts business in Mexico and Central America through its joint venture ADS Mexicana. ADS Mexicana’s Revolving Credit Facility expired on June 22, 2018 and was replaced by an Intercompany Revolving Credit Promissory Note (the “Intercompany Note”) with a borrowing capacity of $12.0 million. The Intercompany Note matures on June 22, 2022. The Intercompany Note indemnifies the ADS Mexicana joint venture partner for 49% of any unpaid borrowing. The interest rates under the Intercompany Note are determined by certain base rates or London Interbank Offered Rate (“LIBOR”) plus an applicable margin based on the Leverage Ratio. As of March 31, 2020 and 2019, there were no borrowings under the Intercompany Note. South American Joint Venture - The Company’s South American Joint Venture manufactures and sells HDPE corrugated pipe in the South American market. ADS is the guarantor for 50% of the South American Joint Venture’s credit facility, and the debt guarantee is shared equally with the joint venture partner. The maximum potential obligation under this guarantee totals $11.0 million as of March 31, 2020. The maximum borrowing permitted under the South American Joint Venture’s credit facility is $22.0 million. This credit facility allows borrowings in either Chilean pesos or US dollars at a fixed interest rate determined at inception of each draw on the facility. The guarantee of the South American Joint Venture’s debt expires on December 31, 2020. ADS does not anticipate any required contributions related to the balance of this credit facility. As of March 31, 2020 and 2019, the outstanding principal balance of the credit facility including letters of credit was $9.3 million and $12.3 million, respectively. As of March 31, 2020, there were no U.S. dollar denominated loans. The weighted average interest rate as of March 31, 2020 was 5.32% on Chilean peso denominated loans. ADS and the South American Joint Venture have entered into shared services arrangements in order to execute the joint venture services. Occasionally, the South American Joint Venture enters into agreements for pipe sales with ADS and its other related parties, which were $0.7 million, $1.3 million and $2.1 million in the fiscal years ended March 31, 2020, 2019 and 2018, respectively. ADS pipe sales to the South American Joint Venture were $0.9 million, $1.2 million and $0.4 million in the fiscal years ended March 31, 2020, 2019 and 2018, respectively. Tigre-ADS USA - Tigre-ADS USA was a joint venture established to manufacture and sell PVC fittings for waterworks, plumbing, and HVAC applications primarily in the United States and Canadian markets. ADS owned 49% of the outstanding shares of capital stock of Tigre-ADS USA. The joint venture represented a continuation of the existing activities of Tigre-ADS USA through its Janesville, Wisconsin manufacturing facility. In April 2018, the Company and the joint venture partner agreed to exchange the Company’s shares of Tigre-ADS USA for a release from the existing debt guarantees. Following the exchange, the Company no longer has an interest in Tigre-ADS USA. Following the exchange of Tigre-ADS USA shares, the Company still considers Tigre-ADS USA a related party as a result of the Company’s joint venture in the South American Joint Venture discussed above. ADS purchased $2.0 million, $0.3 million and $2.0 million of Tigre-ADS USA manufactured products for use in the production of ADS products during fiscal years 2020, 2019 and 2018, respectively.

Debt

Debt	12 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Debt	1 3 . DEBT Long-term debt as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Term Loan Facility $ 648,250 $ — Senior Notes 350,000 — Revolving Credit Facility 100,000 — PNC Credit Agreement — 134,400 Prudential Senior Notes — 100,000 Equipment financing 1,492 2,427 Total 1,099,742 236,827 Unamortized debt issuance costs (2,419 ) (2,293 ) Current maturities (7,955 ) (25,932 ) Long-term debt obligations $ 1,089,368 $ 208,602 Bridge Credit Facility On July 31, 2019, the Company entered into a credit agreement (the “Base Credit Agreement”) by and among the Company, as borrower, Barclays Bank PLC, as administrative agent, the several lenders from time to time party thereto. The Base Credit Agreement provided for a term loan facility in an initial aggregate principal amount of up to $1.3 billion (the “Bridge Loan Facility”), a revolving credit facility in an initial aggregate principal amount of up to $350 million (the “Bridge Revolving Credit Facility”), a letter of credit sub-facility in the initial aggregate available amount of up to $50 million, as a sublimit of such Revolving Credit Facility (the “Bridge L/C Facility”) and a swing line sub-facility in the aggregate available amount of up to $50 million, as a sublimit of the Revolving Credit Facility (together with the Bridge Loan Facility, the Bridge Revolving Credit Facility and the Bridge L/C Facility, the “Bridge Credit Facility”). On July 31, 2019, the Company borrowed approximately $1.3 billion under the Bridge Loan Facility and $145 million under the Bridge Revolving Credit Facility, which amounts were to (i) finance the consideration paid in connection with the closing of the Acquisition, (ii) repay the total outstanding amount as of the Closing Date under the Company’s then existing revolving credit facility with PNC, (iii) repay outstanding amounts of existing indebtedness incurred by Infiltrator Water Technologies under its outstanding credit facility in effect prior to the Acquisition, and (iv) pay certain transaction fees and expenses associated with the Acquisition and the Bridge Loan Facility. Approximately $300.0 million of outstanding borrowings under the Base Credit Agreement were repaid on September 10, 2019 with proceeds from the Company’s public offering of common stock as further described in “Note 19. Net Income Per Share and Stockholders’ Equity” and approximately $300.0 million of outstanding borrowings under the Bridge Loan Facility were repaid on September 23, 2019 with proceeds from the Company’s offering of $350.0 million Senior Notes, as defined and further described below. As a result of this borrowing, on July 31, 2019, the Company initially capitalized approximately $46.9 million of deferred financing fees associated with the Bridge Credit Facility. This amount was later reduced by $14.9 million due to refunds received by ADS. The remaining deferred financing costs were written off due to loss on early extinguishment of debt resulting from the $300.0 million principal payment primarily from the Common Stock Offering, $300.0 million principal payment from the issuance of Senior Notes due 2027, and $700.0 million principal payment from the issuance of the Senior Secured Credit Facility on September 24, 2019. These financings resulted in the Company treating the Bridge Credit Facility as having been extinguished and replaced with the Common Stock Offering, Senior Notes due 2027 and the syndicated Senior Secured Credit Facility for accounting purposes under ASC 470 which is included in interest expense in the Company's Consolidated Statements of Operations, primarily reflects the write-off of unamortized debt issuance costs and discounts. Repayment of Prudential Senior Notes On July 29, 2019, the Company repaid in full all of its and its subsidiaries’ indebtedness and other obligations totaling $104.4 million under that certain Second Amended and Restated Private Shelf Agreement, dated as of June 22, 2017 (as amended the “Shelf Note Agreement”) of the Company’s Senior Notes (“Prudential Senior Notes”), by and among the Company, as issuer, the guarantors from time to time a party thereto, PGIM, Inc., as a purchaser and the other purchasers from time to time a party thereto. The Company repaid the outstanding indebtedness under the Shelf Note Agreement using borrowings from the Company’s Second Amended and Restated Credit Agreement (the “PNC Credit Agreement”) as in effect as of July 29, 2019. Concurrently with the repayment, the Shelf Noteholders authorized and directed PNC Bank, National Association, in its capacity as Collateral Agent (as defined in the Shelf Note Agreement) to release the security interests and liens securing the Shelf Note Agreement and the Shelf Note Agreement was terminated. As a result of the repayment described above, the Company expensed approximately $4.2 million primarily consisting of prepayment premium or penalty associated with the debt payoff activity and the write-off of unamortized deferred financing fees, as the payoff meets the criteria to be accounted for as a debt extinguishment. Repayment of PNC Credit Agreement On the Closing Date, using borrowings of the new Bridge Loan Facility the Company repaid in full all of its and its subsidiaries indebtedness and other obligations totaling $239.2 million under the PNC Credit Agreement. Concurrently with the repayment, all security interests and liens held by the Collateral Agent (as defined in the PNC Credit Agreement) securing the PNC Credit Agreement were terminated and released and the PNC Credit Agreement was terminated. As a result of the repayment described above, the Company expensed approximately $2.0 million primarily consisting of the write-off of unamortized deferred financing fees associated with the debt payoff activity, as the payoff meets the criteria to be accounted for as a debt extinguishment. Issuance of Senior Notes due 2027 On September 23, 2019, the Company issued $350.0 million aggregate principal amount of 5.0% senior notes due 2027 (the “Senior Notes”) pursuant to an Indenture, dated September 23, 2019 (the “Indenture”), among the Company, the guarantors party thereto (the “Guarantors”) and U.S. Bank National Association, as Trustee (the “Trustee”). The Senior Notes are guaranteed by each of the Company’s present and future direct and indirect wholly owned domestic subsidiaries that is a guarantor under the Company's Senior Secured Credit Facility. The Senior Notes were offered and sold either to persons reasonably believed to be “qualified institutional buyers” pursuant to Rule 144A under the Securities Act of 1933 (the “Securities Act”) or to persons outside the United States under Regulation S of the Securities Act. Interest on the Senior Notes will be payable semi-annually in cash in arrears on March 31 and September 30 of each year, commencing on March 31, 2020, at a rate of 5.0% per annum. The Senior Notes will mature on September 30, 2027. The Company used the majority of the net proceeds from the offering of the Senior Notes for the repayment of $300.0 million of its outstanding borrowings under the Company’s Bridge Loan Facility. The deferred financing costs associated with the Senior Notes totaled $2.1 million and are recorded as a direct reduction from the carrying amount of the related debt. The Company may redeem the Senior Notes, in whole or in part, at any time on or after September 30, 2022 at established redemption prices. At any time prior to September 30, 2022, the Company may also redeem up to 40% of the Senior Notes with net cash proceeds of certain equity offerings at a redemption price equal to 105.0% of the principal amount of the Senior Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date. In addition, at any time prior to September 30, 2022, the Company may redeem the Senior Notes, in whole or in part, at a redemption price equal to 100% of the principal amount of the Senior Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date plus an applicable “make-whole” premium. The Indenture contains customary events of default, including, among other things, payment default, failure to comply with covenants or agreements contained in the Indenture or the Senior Notes and certain provisions related to bankruptcy events. The Indenture also contains customary negative covenants. New Senior Secured Credit Facility On September 24, 2019, the Company successfully completed a $700 million syndication of the remaining balance of the Bridge Credit Facility subsequent to the aforementioned Common Stock Offering and Senior Notes due 2027 and in connection with the syndication, the Company amended the Base Credit Agreement (the “Senior Secured Credit Facility”). The Senior Secured Credit Facility reduced the applicable margin utilized in the determination of the interest rate, as well as other provisions. The Senior Secured Credit Facility provides for a term loan facility in an initial aggregate principal amount of $700 million (the “Term Loan Facility”), a revolving credit facility in an initial aggregate principal amount of up to $350 million (the “Revolving Credit Facility”), a letter of credit sub-facility in the initial aggregate available amount of up to $50 million, as a sublimit of such Revolving Credit Facility (the “L/C Facility”) and a swing line sub-facility in the aggregate available amount of up to $50 million, as a sublimit of the Revolving Credit Facility (together with the Term Loan Facility, the Revolving Credit Facility and the L/C Facility, the “Senior Secured Credit Facility”). During fiscal 2020, the Company prepaid $51.8 million of the Term Loan Facility. Letters of credit outstanding at March 31, 2020 amounts to $8.5 million and reduced the availability of the Revolving Credit Facility. In connection with entering into the Senior Secured Credit Facility, the Company capitalized approximately $0.4 million in deferred financing fees. To the extent not previously paid, all then-outstanding amounts under the Term Loan Facility are due and payable on the maturity date of the Term Loan Facility, which is seven years from the Closing Date. Borrowings under the Revolving Credit Facility are available beginning on September 24, 2019 and, to the extent not previously paid, all then-outstanding amounts under the Revolving Credit Facility are due and payable on the maturity date of the Revolving Credit Facility, which is five years from the Closing Date. At the option of the Company, borrowings under the Term Loan Facility and under the Revolving Credit Facility (subject to certain limitations) bear interest at either a base rate (as determined pursuant to the Senior Secured Credit Facility) or at a Eurocurrency Rate, based on LIBOR (as defined in the Senior Secured Credit Facility), plus the applicable margin as set forth therein from time to time. In the case of the Revolving Credit Facility, the applicable margin is based on the Company’s consolidated senior secured net leverage ratio (as defined in the Senior Secured Credit Facility). All borrowings under the Term Loan Facility used to finance the Merger Consideration as described above initially bear interest at a Eurocurrency Rate applicable to Eurocurrency Loans (as defined in the Senior Secured Credit Facility) denominated in U.S. Dollars. The Company is also required to pay a commitment fee that is based upon the undrawn amounts of the Revolving Credit Facility at a rate per annum based upon a calculated ratio as prescribed within the Senior Secured Credit Facility. As of March 31, 2020, the rate the Company was committed to paying on the undrawn portion was equal to 0.2%. The Company’s obligations under the Senior Secured Credit Facility have been secured by granting a first priority lien on substantially all of the Company’s assets (subject to certain exceptions and limitations), and each of StormTech, LLC, Advanced Drainage of Ohio, Inc. and Infiltrator Water Technologies, LLC (collectively the “Guarantors”) has agreed to guarantee the obligations of the Company under the Senior Secured Credit Facility and to secure the obligations thereunder by granting a first priority lien in substantially all of such Guarantor’s assets (subject to certain exceptions and limitations). Principal Maturities - Maturities of long-term debt (excluding interest and deferred financing costs) as of March 31, 2020 are summarized below: Fiscal Years Ending March 31, (Amounts in thousands) 2021 2022 2023 2024 2025 Thereafter Total Principal maturities $ 7,955 $ 7,532 $ 7,000 $ 7,000 $ 107,000 $ 963,255 $ 1,099,742

Derivative Transactions

Derivative Transactions	12 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Derivative Transactions	1 4 . DERIVATIVE TRANSACTIONS The Company uses interest rate swaps and commodity options in the form of collars and swaps to manage its various exposures to interest rate and commodity price fluctuations. For the interest rate swap executed on June 28, 2017, gains and losses resulting from the difference between the spot rate and applicable base rate is recorded in Interest expense. The Company’s interest rate swap was terminated during the year ended March 31, 2020 in conjunction with the new Senior Secured Credit Facility. For collars and commodity swaps, contract settlement gains and losses are recorded in the Consolidated Statements of Operations in Derivative gains and other income, net. Gains and losses related to mark-to-market adjustments for changes in fair value of the derivative contracts are also recorded in the Consolidated Statements of Operations in Derivative gains and other income, net. A summary of the fair values for the various derivatives at March 31, 2020 and 2019 is presented below: 2020 Assets Liabilities (Amounts in thousands) Receivables Other assets Other accrued liabilities Other liabilities Diesel fuel option collars and swaps $ 21 $ 15 $ (2,000 ) $ (228 ) 2019 Assets Liabilities (Amounts in thousands) Receivables Other assets Other accrued liabilities Other liabilities Diesel fuel option collars and swaps $ 127 $ 62 $ (201 ) $ (82 ) Foreign exchange forward contracts — — (60 ) — Interest rate swaps 566 522 — — The Company recorded net losses and net (gains) on mark-to-market adjustments for changes in the fair value of derivative contracts as well as net losses and net (gains) on the settlement of derivative contracts as follows: Net Unrealized Mark to Market Losses (Gains) (Amounts in thousands) 2020 2019 2018 Interest rate swaps $ 1,029 $ 1,712 $ (2,801 ) Foreign exchange forward contracts — 60 — Diesel fuel option collars 2,099 574 (443 ) Total net unrealized mark to market losses (gains) $ 3,128 $ 2,346 $ (3,244 ) Net Realized Losses (Gains) (Amounts in thousands) 2020 2019 2018 Interest rate swaps $ 378 $ (329 ) $ — Foreign exchange forward contracts 102 (163 ) — Diesel fuel option collars 357 (698 ) (476 ) Total net realized losses (gains) $ 837 $ (1,190 ) $ (476 )

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Mar. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	1 5 . COMMITMENTS AND CONTINGENCIES Purchase Commitments The Company has historically secured supplies of resin raw material by agreeing to purchase quantities during a future given period at a fixed price. These purchase contracts typically ranged from 1 to 12 months and occur in the ordinary course of business. The Company, also, enters into equipment purchase contracts with manufacturers. Litigation and Other Proceedings The Company is involved from time to time in various legal proceedings that arise in the ordinary course of business, including but not limited to commercial disputes, environmental matters, employee related claims, intellectual property disputes and litigation in connection with transactions including acquisitions and divestitures. The Company does not believe that such litigation, claims, and administrative proceedings will have a material adverse impact on the Company’s financial position or results of operations. The Company records a liability when a loss is considered probable, and the amount can be reasonably estimated. Other Commitments and Contingencies In March 2019, the Company initiated an internal investigation process, under the guidelines of the Company’s Code of Business Conduct and Ethics, into its consolidated joint venture affiliate ADS Mexicana’s senior management’s ethical and business conduct, as well as compliance of certain products with, along with considerations into Mexican laws and regulations over the last 12 months. The Company has concluded that the current estimate of probable losses resulting from the investigation is not material to our consolidated financial statements, however due to the inherent uncertainties in determining the use, installation application and location of our ADS Mexicana products sold, along with the consideration of Mexican laws and regulations related to warranty and product liability obligations, the Company is unable to determine the maximum potential future losses that may occur, which could be material to the consolidated financial statements.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Mar. 31, 2020
Postemployment Benefits [Abstract]
Employee Benefit Plans	1 6 . EMPLOYEE BENEFIT PLANS Employee Stock Ownership Plan (“ESOP”) - The Company established the Advanced Drainage Systems, Inc. ESOP (the “ESOP” or the “Plan”) effective April 1, 1993. The Plan was funded through a transfer of assets from our tax-qualified profit-sharing retirement plan, as well as a 30-year term loan from ADS. Within 30 days following the repayment of the ESOP loan, which will occur no later than March 2023, the ESOP committee can direct the shares of redeemable convertible preferred stock owned by the ESOP to be converted into shares of the Company’s common stock. The Plan operates as a tax-qualified leveraged ESOP and was designed to enable eligible employees to acquire stock ownership interest in ADS. Employees of ADS who have reached the age of 18 are generally eligible to participate in the Plan on March 31 after six months of service. Upon retirement, disability, death, or vested terminations, (i) a participant or designated beneficiary may elect to receive the amount in their account attributable to the 1993 transfer of assets from our tax-qualified profit sharing retirement plan in the form of cash or ADS stock with any fractional shares paid in cash; (ii) stock credited to the participants’ ESOP stock account resulting from the ESOP’s loan repayments are distributed in the form of ADS stock, and (iii) amounts credited to the participants’ ESOP cash account are distributed in the form of cash. Upon attainment of age 50 and seven years of participation in the Plan, a participant may elect to diversify specified percentages of the number of shares of ADS stock credited to the participant’s ESOP stock account in compliance with applicable law. The Company is obligated to make contributions to the Plan, which, when aggregated with the Plan’s dividends on the Plan’s unallocated shares of redeemable convertible preferred stock, equal the amount necessary to enable the Plan to make its regularly scheduled payments of principal and interest due on its term loan to ADS. As the Plan makes annual payments of principal and interest, an appropriate percentage of preferred stock is allocated to ESOP participants’ accounts in accordance with plan terms that are compliant with applicable Internal Revenue Code and regulatory provisions. The carrying value of redeemable convertible preferred stock held by the ESOP trust, but not yet earned by the ESOP participants or used for dividends, is reported as Deferred compensation — unearned ESOP shares within the Mezzanine equity section of our Consolidated Balance Sheets. Compensation expense and related dividends paid with ESOP shares for services rendered throughout the period are recognized based upon the annual fair value of the shares allocated. Deferred compensation — unearned ESOP shares is relieved at fair value, with any difference between the annual fair value and the carrying value of shares when allocated being added to Additional paid in capital. The fair value of the shares allocated was $22.70, $19.90, and $20.00 per share of redeemable convertible preferred stock at March 31, 2020, 2019, and 2018, respectively, resulting in an average annual fair value per share of $21.31, $19.95, and $18.40 per share for the fiscal years ended March 31, 2020, 2019, and 2018, respectively. During the fiscal years ended March 31, 2020, 2019, and 2018, the Company recognized compensation expense of $20.1 million, $15.3 million, and $11.7 million, respectively, related to allocation of ESOP shares to participants. Required dividends on allocated shares are generally passed through and paid in cash to the participants and required dividends on unallocated shares are paid in cash to the Plan and generally used to service the Plan’s debt. The ESOP committee directed the Plan trustee to retain dividends on unallocated ADS shares rather than to service the Plan’s debt. In the fiscal years ended March 31, 2020, 2019, and 2018, the Company recognized compensation expense and the trustee retained $0.0 million, $3.3 million and $3.2 million, respectively, for dividends on unallocated ADS shares. These dividends were allocated to participants based on the total shares in their account in relation to total shares allocated at March 31, 2020 and 2019. Redeemable Convertible Preferred Stock - The Trustee of the Company’s ESOP has the ability to put shares of the redeemable convertible preferred stock to the Company absent a market for the Company’s common stock, and as a result the redeemable convertible preferred stock is classified as Mezzanine equity in the Company’s Consolidated Balance Sheets. The put option requirements of the Internal Revenue Code apply in the event that the Company’s common stock is not a registration type class of security or its trading has been restricted. Therefore, the holders of Redeemable convertible preferred stock have a put right to require the Company to repurchase such shares in the event that the common stock is not listed for trading or otherwise quoted on the NYSE, AMEX, NASDAQ, or any other market more senior than the OTC Bulletin Board. As of March 31, 2020 , the applicable redemption value was $ per share as there were no unpaid cumulative dividends. Given that the event that may trigger redemption of the Redeemable convertible preferred stock (the listing or quotation on a market more senior than the OTC Bulletin Board) is not solely within the Company’s control, the redeemable convertible preferred stock is presented in the mezzanine equity section of the Consolidated Balance Sheets. As of March 31, 2020, the Company did not adjust the carrying value of the redeemable convertible preferred stock to its redemption value or recognize any changes in fair value as the Company did not consider it probable that the Redeemable convertible preferred stock would become redeemable. The Redeemable convertible preferred stock has a required cumulative 2.5% dividend (based on the liquidation value of $0.7818 per share) and is convertible at a rate of 0.7692 shares of common stock for each share of Redeemable convertible preferred stock. The 2.5% annual dividend is payable in cash or additional shares of the Redeemable convertible preferred stock. During the first quarter of fiscal 2020, the Board of Directors approved the 2.5% annual dividend to be paid in cash on March 31, 2020 to stockholders of record as of March 15, 2020. The Redeemable convertible preferred stock has a liquidation value of $0.7818 per share that must be paid before any distribution or payment may be made to holders of common stock in the event of any voluntary or involuntary liquidation, dissolution or winding up of the affairs of ADS. During fiscal year ended March 31, 2020, the Board of Directors approved a special cash dividend of $1.00 per share. See “Note 19. Net Income Per Share and Stockholders’ Equity” for additional information. Cash and stock dividends on allocated Redeemable convertible preferred stock for the fiscal years ended March 31, 2020 and 2019, respectively, are summarized in the following table. (Amounts in thousands) 2020 2019 Quarterly cash dividends $ 10,840 $ 1,903 Annual cash dividends 7 10 Total cash dividends $ 10,847 $ 1,913 Annual stock dividend 359 134 Annual cash dividend 7 10 Total ESOP required dividends $ 366 $ 144 Allocated shares 18,756 7,392 Required dividend per share 0.0195 0.0195 Required dividends $ 366 $ 144 In the fiscal years ended March 31, 2020 and 2019, 1.0 million and 0.8 million shares of redeemable convertible preferred stock, respectively, were allocated to the ESOP participants, including, in addition to the cash dividends, 0.4 million and less than 0.1 million preferred shares allocated as dividends, respectively. Executive Retirement Expense - ADS has employment agreements with certain executives that include potential payments to be made to those executives upon termination. The terms of the termination payments vary by executive, but are generally based on current base salary and bonus levels at the time of termination. The contractual termination payments vest upon either (1) certain contingent occurrences terminating employment such as death, disability, layoff, the executive voluntarily quitting due to a breach of covenants by the Company or for other “good reason” or (2) the executive reaching a specified retirement age while still working for the Company, as defined in the individual employee agreement. The Company accrues a liability from the effective date of the executive’s employment agreement to the date the executive reaches the required retirement age while working for the Company, which is considered the service period for this obligation. The liability is estimated based on each executive’s current base salary and bonus levels. Because the executives vest in the termination payments equally over the relevant service period, the Company recognizes the related compensation expense based on the straight-line method over the service period. If an executive terminates their employment prior to reaching the required retirement age, no payment is required and the previously recorded compensation expense for that executive is reversed and recorded as a benefit to compensation expense in the period the executive terminates employment. The compensation (benefit) expense recorded related to the executive termination payments for the fiscal years ended March 31, 2020, 2019, and 2018 was $0.2 million, $(0.2) million and $1.5 million, respectively, and is included in General and administrative expenses in the Consolidated Statements of Operations. As of March 31, 2020 and 2019, the executive termination payment obligation was $2.6 million and $4.3 million, respectively, and is included in Other accrued liabilities and Other liabilities in the Consolidated Balance Sheets. Profit-Sharing Plan - The Company has a tax-qualified profit-sharing retirement plan with a 401(k) feature covering substantially all U.S. eligible employees. The Company did not make employer contributions to this plan in the fiscal years ended March 31, 2020, 2019, and 2018. The Company has defined contribution postretirement benefit plans covering Infiltrator Water Technologies and Canadian employees. The Company recognized costs of $0.5 million, $0.4 million and $0.7 million in the fiscal years ended March 31, 2020, 2019, and 2018. COVID-19 Pandemic Pay – In fiscal 2020, the Company communicated to all hourly employees that each would be entitled to the equivalent of two weeks, or 80 hours, of pandemic pay regardless of whether they experienced any interruption of employment. The Company recognized pandemic pay costs in Costs of goods sold on the Company’s Consolidated Statement of Operations and accrued pandemic pay liability in Other accrued liabilities on the Company’s Consolidated Balance Sheet of $4.8 million in the fiscal year ended March 31, 2020

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Mar. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	1 7 . STOCK-BASED COMPENSATION The Company has several programs for stock-based payments to employees and directors, including stock options and restricted stock. Stock-based compensation expense is recorded in General and administrative expenses, Selling expenses and Cost of goods sold in the Consolidated Statements of Operations. The Company recognized stock-based compensation expense in the following line items on the Consolidated Statements of Operations for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Component of income before income taxes: Cost of goods sold $ 897 $ 317 $ 179 Selling expenses 426 180 105 General and administrative expenses 10,946 6,035 6,837 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121 The following table summarizes stock-based compensation expense by award type for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Stock-based compensation expense: Equity-classified stock options 2,554 2,550 4,148 Restricted stock 3,807 2,064 1,741 Performance-based restricted stock units 4,682 869 — Non-employee director 1,226 1,049 1,232 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121 The following table summarizes the assumptions used in estimating the fair value of stock options: 2020 2019 2018 Common stock price $27.44 - $41.85 $25.75 - $27.99 $19.35 - $22.95 Expected stock price volatility 30.1% - 30.9% 30.3% - 31.1% 32.1% - 35.6% Risk-free interest rate 1.4% - 2.3% 2.9% - 3.1% 1.9% - 2.2% Weighted-average expected option life (years) 6.0 6.0 5.6 - 6.0 Dividend yield 0.9% - 1.3% 1.1% - 1.2% 1.1% - 1.5% 2000 and 2013 Stock Options Plans Equity classified stock option awards are measured based on the grant date estimated fair value of each award. Compensation expense for stock options is recognized on a straight-line basis over the employee’s requisite service period, which is generally the vesting period of the grant. The Company estimates the fair value of stock options using a Black-Scholes option-pricing model. 2000 Plan - The Company’s 2000 stock option plan (“2000 Plan”) provided for the issuance of statutory and non-statutory stock options to management based upon the discretion of the Board of Directors. The plan generally provided for grants with the exercise price equal to fair value on the date of grant, which vest in three equal annual amounts beginning in year five and expire after approximately 10 years from issuance. The Company had no shares available for grant under the 2000 Plan as of March 31, 2020. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 82 $ 14.64 4.3 Granted — — — Exercised (8 ) 13.87 — Forfeited (3 ) 15.74 — Outstanding at end of year 71 14.69 3.4 Vested at end of year 37 13.73 2.8 Unvested at end of year 34 15.74 4.0 Fair value of options granted during the year $ — All outstanding options are expected to vest. The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 54 $ 6.76 Granted — — Vested (17 ) 8.72 Forfeitures (3 ) 8.72 Unvested at end of year 34 $ 8.72 As of March 31, 2020, there was a total of $0.1 million of unrecognized compensation expense related to unvested stock option awards under the 2000 plan that will be recognized as an expense as the awards vest over the remaining weighted average service period of 1.3 years. During the fiscal year end March 31, 2020, 0.1 million shares vested. No options vested during fiscal years ended March 31, 2019 and 2018. No options were granted during the fiscal years ended March 31, 2020, 2019, and 2018. The aggregate intrinsic value for options outstanding and currently exercisable as of March 31, 20 20 was $ million and $ million, respectively. The total intrinsic value of options exercised during the fiscal years ended March 31, 2020, 2019, and 2018 were $ million, $ million and $ 0.5 million, respectively. 2013 Plan - The Company’s 2013 stock option plan (“2013 Plan”) provided for the issuance of non-statutory common stock options to management subject to the Board’s discretion. The plan generally provided for grants with the exercise price equal to fair value on the date of grant. The grants generally vest in three to five equal annual amounts beginning in year one and expire after approximately 10 years from issuance. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 1,120 $ 16.81 4.9 Granted — — — Exercised (555 ) 14.11 — Forfeited — — — Outstanding at end of year 565 19.45 4.7 Vested at end of year 542 19.25 4.6 Unvested at end of year 23 24.12 6.0 Fair value of options granted during the year $ — All outstanding options are expected to vest. The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 121 $ 7.68 Granted — — Vested (98 ) 7.80 Forfeited — — Unvested at end of year 23 $ 7.20 As of March 31, 2020, there was a total of $0.1 million of unrecognized compensation expense related to unvested stock option awards under the 2013 Plan that will be recognized as an expense as the awards vest over the remaining weighted average service period of 0.9 years. The aggregate intrinsic value for options outstanding and currently exercisable as of March 31, 2020 was $5.6 million and $5.5 million, respectively. The total fair value of options that vested during the fiscal years ended March 31, 2020, 2019, and 2018 were $0.8 million, $2.6 million, and $4.7 million, respectively. The total intrinsic value of options exercised during the fiscal year ended March 31, 2020 was $13.2 million. 2008 Restricted Stock Plan On September 16, 2008, the Board of Directors adopted the restricted stock plan, which provided for the issuance of restricted stock awards to certain key employees. The restricted stock generally vest ratably over a five-year Employees with restricted stock have the right to dividends on the shares awarded (vested and unvested) in addition to voting rights on non-forfeited shares. The fair value of restricted stock is based on the fair value of the Company’s common stock. Compensation expense is recognized on a straight-line basis over the employee’s requisite service period, which is generally the vesting period of the grant. The Company had no shares available for grant under this plan as of March 31, 2020. The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 44 $ 24.17 Granted — — Vested (37 ) 24.18 Forfeited (1 ) 24.20 Unvested at end of year 6 $ 24.10 The Company expects all restricted stock grants to vest. At March 31, 2020, there was approximately $0.1 million of unrecognized compensation expense related to the restricted stock that will be recognized over the weighted average remaining service period of 1.0 years. 2017 Omnibus Plan On May 24, 2017, the Board of Directors approved the 2017 Omnibus Incentive Plan (the “2017 Incentive Plan”) which was approved by the Company’s stockholders on July 17, 2017. The 2017 Incentive Plan provides for the issuance of a maximum of 3.5 million shares of the Company’s common stock for awards made thereunder, which awards may consist of stock options, restricted stock, restricted stock units, stock appreciation rights, phantom stock, cash-based awards, performance awards (which may take the form of performance cash, performance units or performance shares) or other stock-based awards. The Company had approximately 1.8 million shares available for awards as of March 31, 2020. The 2017 Incentive Plan replaces the 2000 Incentive Stock Option Plan, 2008 Restricted Stock Plan, 2013 Stock Option Plan, and 2014 Non-Employee Director Compensation Plan (the “Prior Plans”) and no further grants will be made under the prior plans. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 457 $ 23.19 8.9 Granted 336 27.51 — Exercised (8 ) 25.75 — Forfeited — — — Outstanding at end of year 785 25.01 8.4 Vested at end of year 212 22.04 7.7 Unvested at end of year 573 26.11 8.7 Fair value of options granted during the year 8.02 The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 388 $ 7.19 Granted 336 8.02 Vested (151 ) 7.01 Forfeited — — Unvested at end of year 573 $ 7.73 The aggregate intrinsic value for options outstanding and exercisable as of March 31, 2020 was $3.5 million and $1.6 million, respectively. There were 0.1 million options that were exercised during the fiscal year ended March 31, 2020. The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 172 $ 25.02 Granted 308 31.96 Vested (90 ) 25.63 Forfeited (2 ) 27.13 Unvested at end of year 388 $ 30.38 At March 31, 2020, there was approximately $8.2 million of unrecognized compensation expense related to the restricted stock that will be recognized over the weighted average remaining service period of 2.1 years. The total fair value of restricted stock that vested during fiscal year ended March 31, 2020 and 2019 was $2.3 million and $2.0 million, respectively. During the fiscal year ended March 31, 2018, no restricted stock vested. The information about the performance units granted under the 2017 Omnibus Plan is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 115 $ 25.85 Granted 274 33.27 Vested — — Forfeited — — Unvested at end of year 389 $ 31.07 At March 31, 2020, there was approximately $9.6 million of unrecognized compensation expense related to the performance units that will be recognized over the weighted average remaining service period of 1.9 years. For the performance units, 50% of the award is based upon the achievement of certain levels of Return on Invested Capital for the performance period and 50% is based upon the achievement of certain levels of Free cash flow for the performance period. During fiscal year 2020, the Company modified the achievement levels of the awards due to the Acquisition of Infiltrator Water Technologies. The modification did not result in any incremental compensation expense. The performance units have a 3-year performance period from April 1, 2019 through March 31, 2022. The performance units, and any accrued dividend equivalents, will be settled in shares of the Company’s common stock, if the applicable performance and service conditions are satisfied. In addition to the performance units based on ADS performance, the Company issued performance units based on the achievements of other performance targets. During fiscal year 2020, the Company granted 0.1 million units with a grant date fair value of $ million, subject to achieving predetermined synergies of the now consolidated legacy ADS business and Infiltrator Water Technologies. The Company further granted 0.1 million units with a grant date fair value of $ 2.7 million, subject to performance conditions of the Infiltrator Water Technologies reportable segment. For the performance units based on the Infiltrator Water Technologies reportable segment, 75% of the award is based upon the achievement of certain levels of Infiltrator Water Technologies Adjusted EBITDA for the performance period and 25% is based upon the achievement of certain levels of Infiltrator Water Technologies Free c ash f low for the performance period . These two performance unit grants have a 3-year performance period from August 1, 2019 through March 31, 2022 . During the fiscal year ended March 31, 20 20 and 2019 , the weighted average gran t date fair value of performance units granted was $ 33.27 and $ 25.84 , respectively . During the fiscal year ended March 31, 20 20 and 2019 , the total fair value of performance units that vested was $ 0.0 million and $ 0.1 million. During the fiscal year ended March 31, 2018, no performance units vested

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	18. INCOME TAXES The components of Income before income taxes for the fiscal years ended March 31 are as follows: (Amounts in thousands) 2020 2019 2018 United States $ (186,209 ) $ 103,559 $ 72,109 Foreign 6,595 8,051 4,833 Total $ (179,614 ) $ 111,610 $ 76,942 The components of Income tax expense for the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 2018 Current: Federal $ 10,867 $ 11,575 $ 17,107 State and local 4,655 3,998 3,541 Foreign 1,546 2,050 2,242 Total current tax expense 17,068 17,623 22,890 Deferred: Federal 210 11,745 (11,236 ) State and local (1,228 ) 1,795 (55 ) Foreign (1,958 ) (1,114 ) (188 ) Total deferred tax expense (benefit) (2,976 ) 12,426 (11,479 ) Total Income tax expense $ 14,092 $ 30,049 $ 11,411 For the fiscal years ended March 31, the effective tax rate varied from the statutory Federal income tax rate as a result of the following factors: 2020 2019 2018 Federal statutory rate 21.0 % 21.0 % 31.5 % ESOP stock appreciation, ESOP dividends and special dividend (a) (30.3 ) 3.2 5.4 Effect of tax rate of foreign subsidiaries 0.6 (0.3 ) 0.7 State and local taxes—net of federal income tax benefit (1.7 ) 4.6 3.6 Uncertain tax position change 1.2 (1.3 ) 0.3 Impact of tax reform — — (19.4 ) Equity-based compensation 1.1 (0.4 ) 0.5 Return to provision - federal and state 0.3 (0.2 ) (5.0 ) Qualified production activity deduction — — (2.5 ) Executive compensation (0.8 ) 1.1 0.1 Net operating losses 1.9 — — Credits and incentives 0.7 (1.0 ) (0.5 ) Other (1.9 ) 0.2 0.1 Effective rate (7.9 )% 26.9 % 14.8 % (a) This includes the special dividend paid in the first quarter of fiscal 2020 that resulted in $246.8 million in additional stock-based compensation. Of the total stock-based compensation expense and dividends paid, approximately $242.9 million related to non-deductible stock appreciation and deductible dividends. This decreased the effective tax rate by 28.4%. See “Note 19. Net Income Per Share and Stockholders’ Equity” for additional information. As discussed in “Note 4. Acquisitions”, the Company acquired Infiltrator Water Technologies on July 31, 2019. During the year ended March 31, 2020, as part of the purchase price, approximately $132.4 million was attributed to deferred tax liabilities. Of the $132.4 million, $82.3 million related to the step up of GAAP basis for fair market valuations, while the remaining $50.1 million were acquired deferred tax liabilities. Of the total $82.3 million, $80.2 million was attributed to intangibles. The Company also acquired a federal net operating loss of $24.0 million. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act ("CARES Act") was signed into law. The CARES Act provides that net operating losses arising in a tax year beginning in 2018, 2019, or 2020 can be carried back five years. As a result, the Company has recognized an income tax benefit of $3.4 million related to the federal net operating loss from the acquisition of Infiltrator Water Technologies. The Company continues to evaluate the new law, and we do not expect either the U.S. or non-U.S. corporate income tax provisions of the CARES Act to have a material impact on our income tax (benefit) provision. As of March 31, 2020, the Company has approximately $26.5 million of undistributed earnings that are intended to be reinvested indefinitely with the exception of cash dividends paid by our ADS Mexicana joint venture and the distribution paid by our Canadian subsidiary during the fiscal year. It is not practicable to estimate the amount of U.S. tax, which would primarily relate to withholding tax, that might be payable on the eventual remittance of such undistributed earnings. The tax effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at March 31 were comprised of: (Amounts in thousands) 2020 2019 Deferred tax assets: Receivable and other allowances $ 1,122 $ 1,546 Inventory 2,065 3,217 Stock-based compensation 2,770 3,186 Worker’s compensation 2,317 2,063 Net operating loss and credit carryforwards 2,059 152 Operating lease liabilities 6,160 - Other 5,562 4,673 Total deferred tax assets 22,055 14,837 Less: valuation allowance (941 ) (269 ) Total net deferred tax assets 21,114 14,568 Deferred tax liabilities: Intangible assets 121,276 2,512 Property, plant and equipment 63,649 52,218 Operating lease assets 6,147 - Goodwill 4,527 4,078 Other 600 1,385 Total deferred tax liabilities 196,199 60,193 Net deferred tax liability $ 175,085 $ 45,625 Net deferred tax assets and liabilities are included in Other assets and Deferred tax liabilities, respectively, on the Consolidated Balance Sheets. The related balances at March 31 were as follows: (Amounts in thousands) 2020 2019 Net non-current deferred tax assets $ 531 $ 338 Net non-current deferred tax liabilities 175,616 45,963 As a result of the acquisition of Infiltrator Water Technologies, the Company acquired state net operating losses (“NOLs”) and state credit carryforward attributes. The Company has recorded deferred tax assets related to state NOLs of $0.9 million as of March 31, 2020, with carryforward periods ranging from 5 to 20 years. Any losses not utilized within a specific state’s carryforward period will expire. A valuation allowance has been recorded against $0.1 million of these deferred tax assets as of March 31, 2020 for state NOLs that the Company does not expect to realize within their respective carryforward periods. Tax benefits associated with state tax credits will also expire if not utilized and amounted to $0.8 million at March 31, 2020. A valuation allowance in the amount of $0.5 million has been established related to state credits the Company does not expect to utilize. Deferred tax assets related to foreign NOLs were $0.3 million as of March 31, 2020 with carryforward periods ranging from 20 years to indefinite carryforward periods. Any losses not utilized within a specific carryforward period will expire. A valuation allowance has been recorded against $0.1 million of these deferred tax assets as of March 31, 2020 for foreign NOLs that the Company does not expect to realize within their respective carryforward periods. Accounting for Uncertain Tax Positions As of March 31, 2020, The Company had unrecognized tax benefit of $3.3 million, which if resolved favorably, would reduce income tax expense by $3.3 million. A reconciliation of the beginning and ending amounts of unrecognized tax benefits for the years ended March 31, 2020, 2019, and 2018 is as follows: (Amounts in thousands) 2020 2019 2018 Balance at beginning of year $ 5,681 $ 7,593 $ 6,196 Tax positions taken in current year — 164 81 Decreases in tax positions for prior years (1,398 ) (198 ) — Increases in tax positions for prior years 1,907 136 5,108 Settlements (124 ) (200 ) — Lapse of statute of limitations (2,589 ) (1,595 ) (3,940 ) Foreign translation adjustment (134 ) (219 ) 148 Balance at end of year $ 3,343 $ 5,681 $ 7,593 The short-term portion of the unrecognized tax benefit of $1.5 million at March 31, 2020 is recorded in Other Accrued liabilities on the Company’s Consolidated Balance Sheet. The long-term portion of unrecognized tax benefits are recorded in Other liabilities in the Company’s Consolidated Balance Sheets. These amounts include potential accrued interest and penalties of $0.8 million and $1.5 million at March 31, 2020 and 2019, respectively. The Company believes that over the next twelve months, it is reasonably possible that up to $1.5 million of unrecognized tax benefits could be resolved as the result of settlements of audits and the expiration of statutes of limitation. Final settlement of these issues may result in payments that are more or less than this amount, but the Company does not anticipate that the resolution of these matters will result in a material change to its consolidated financial position or results of operations. The Company is currently open to audit under the statute of limitations by the IRS for the fiscal years ended March 31, 2017 through March 31, 2020. The majority of the Company’s state income tax returns are open to audit under the statute of limitations for the years ended March 31, 2016 through March 31, 2020. The foreign income tax returns are open to audit under the statute of limitations for the years ended March 31, 2016 through March 31, 2020.

Net Income Per Share and Stockh

Net Income Per Share and Stockholders' Equity	12 Months Ended
	Mar. 31, 2020
Net Income Per Share And Stockholders Equity [Abstract]
Net Income Per Share and Stockholders' Equity	1 9 . NET INCOME PER SHARE AND STOCKHOLDERS’ EQUITY Basic net income per share is calculated by dividing the Net income available to common stockholders by the weighted-average number of common shares outstanding during the period, without consideration for common stock equivalents. Diluted net income per share is computed by dividing the Net income available to common stockholders by the weighted-average number of common stock equivalents outstanding for the period. Holders of certain unvested restricted stock have non-forfeitable rights to dividends when declared on common stock, and holders of redeemable convertible preferred stock participate in dividends on an as-converted basis when declared on common stock. As a result, unvested restricted stock and redeemable convertible preferred stock meet the definition of participating securities, which requires us to apply the two-class method to compute both basic and diluted net income per share. The two-class method is an earnings allocation formula that treats participating securities as having rights to earnings that would otherwise have been available to common stockholders. The dilutive effect of stock options and unvested restricted stock is based on the more dilutive of the treasury stock method or the diluted two-class method. In computing diluted net income per share, income available to common stockholders used in the basic net income per share calculation (numerator) is adjusted, subject to sequencing rules, for certain adjustments that would result from the assumed issuance of potential common shares. After the effective date of the IPO, management’s intent is to share settle; therefore, these shares are included in the calculation from July 26, 2014 through March 31, 2020, if dilutive. For purposes of the calculation of diluted net income per share, stock options and unvested restricted stock are considered to be potential common stock and are only included in the calculations when their effect is dilutive. The Company’s redeemable common stock is included in the weighted-average number of common shares outstanding for calculating basic and diluted net income per share. The following table presents information necessary to calculate net income per share for the fiscal years ended March 31, 2020, 2019, and 2018, as well as potentially dilutive securities excluded from the weighted average number of diluted common shares outstanding because their inclusion would have been anti-dilutive: (Amounts in thousands, except per share data) 2020 2019 2017 NET INCOME PER SHARE — BASIC: Net (loss) income attributable to ADS $ (193,174 ) $ 77,772 $ 62,007 Adjustment for: Dividends paid to redeemable convertible preferred stockholders (11,206 ) (2,047 ) (1,858 ) Dividends paid to unvested restricted stockholders (338 ) (69 ) (49 ) Net income available to common stockholders and participating securities (204,718 ) 75,656 60,100 Undistributed income allocated to participating securities — (5,474 ) (4,514 ) Net income available to common stockholders — Basic (204,718 ) 70,182 55,586 Weighted average number of common shares outstanding — Basic 63,820 57,025 55,696 Net (loss) income per common share — Basic $ (3.21 ) $ 1.23 $ 1.00 NET INCOME PER SHARE — DILUTED: Net income available to common stockholders — Diluted (204,718 ) 70,182 55,586 Weighted average number of common shares outstanding — Basic 63,820 57,025 55,696 Assumed restricted stock - nonparticipating — 39 — Assumed exercise of stock options — 547 638 Weighted average number of common shares outstanding — Diluted 63,820 57,611 56,334 Net (loss) income per common share — Diluted $ (3.21 ) $ 1.22 $ 0.99 Potentially dilutive securities excluded as anti- dilutive 14,449 5,966 6,167 Common Stock Offering – On September 10, 2019, the Company issued and sold an aggregate of 10,350,000 shares of common stock, $0.01 par value per share, which included the full exercise of the underwriters’ option to purchase additional shares, at a price of $29.75 per share, before underwriting discounts and commissions. The common stock was sold pursuant to the Company’s shelf registration statement and related prospectus supplement. The Company received proceeds of $293.6 million from the issuance after deducting underwriting discounts and commissions and offering expenses. The Company used the net proceeds for the repayment of a portion of the outstanding borrowings under the Senior Secured Credit Facility. Stockholders’ Equity - The Company did no t repurchase any shares of common stock during fiscal years 2020 and 2019. In February 2017, the Company’s Board of Directors authorized the Company to repurchase up to $ 50 million of ADS common stock in accordance with applicable securities laws. As of March 31, 2020 , approximately $ 42.1 million of common stock may be repurchased under the authorization. The repurchase program does not obligate the Company to acquire any particular amount of common stock and may be suspended or terminated at any time at the Company’s discretion . Special Dividend and the Employees Stock Ownership Plan (“ESOP”) - During fiscal year ended March 31, 2020, the Board of Directors approved a special cash dividend of $1.00 per share and quarterly dividends of $0.09 per share. The special and quarterly dividend were paid to all stockholders on June 14, 2019 to stockholders of record at the close of business on June 3, 2019. The total dividend payment was $81.6 million. The dividends received by the unallocated redeemable convertible preferred stock held in the ESOP trust was used to pay $12.0 million of the ESOP loan back to the Company resulting in approximately 11.6 million shares of the Company’s redeemable convertible preferred stock being allocated to ESOP participants. The Company recognized $246.8 million in stock-based compensation expense based on the fair value on the date the Board of Directors approved the special dividend. The Board of Director’s approval committed the ESOP to use those proceeds to pay down the ESOP loan. The special dividend compensation expense was recognized in Cost of goods sold - ESOP special dividend compensation and Selling, general and administrative expenses - ESOP special dividend compensation on the Company’s Consolidated Statement of Operations. The Company’s ESOP is further described in “Note 16. Employee Benefit Plans”

Other Accrued Liabilities

Other Accrued Liabilities	12 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Other Accrued Liabilities	20. OTHER ACCRUED LIABILITIES Other accrued liabilities as of fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Accrued compensation and benefits (1) $ 33,215 $ 18,108 Accrued rebate liability (2) 14,479 12,313 Lease liability - Operating leases 7,757 — Self-insurance accruals 12,486 11,697 Other 33,179 19,783 Total accrued liabilities $ 101,116 $ 61,901 (1) Accrued compensation and benefits is primarily comprised of accrued payroll, bonuses and commissions. (2) Accrued rebate liability represents the Company’s estimated rebates to be paid to customers.

Business Segment Information

Business Segment Information	12 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Business Segment Information	2 1 . BUSINESS SEGMENT INFORMATION Following the Acquisition of Infiltrator Water Technologies, the Company revised its reportable segments to reflect how the Chief Operating Decision Maker (“CODM”) currently reviews financial information and makes operational decisions. After the Acquisition, ADS operates its business in three distinct reportable segments: “Pipe”, “International” and “Infiltrator Water Technologies.” “Allied Products & Other” represents the Company’s Allied Products and all other business segments. “Pipe” and “Allied Products & Other” were previously included as Domestic. With the change in reportable segments, the CODM is now evaluating segment reporting based on Net Sales and Segment Adjusted Gross Profit. The Company calculated Segment Adjusted Gross Profit as net sales less costs of goods sold, depreciation and amortization, stock-based compensation, non-cash charges and certain other expenses Pipe – The Pipe segment manufactures and markets high performance thermoplastic corrugated pipe throughout the United States. The Company maintains and serves these markets through product distribution relationships with many of the largest national and independent waterworks distributors, buying groups and co-ops, major national retailers as well as an extensive network of hundreds of small to medium-sized distributors across the U.S. Products include single wall pipe, N-12 HDPE pipe sold into the Storm sewer, Infrastructure and Agriculture markets, High Performance polypropylene pipe sold into the Storm sewer, Infrastructure and sanitary sewer markets. Products are designed primarily for storm water management in the construction and infrastructure marketplace across a broad range of end markets and applications, including non-residential, residential, agriculture and infrastructure. Products are manufactured using HDPE and polypropylene plastic material. Infiltrator Water Technologies – Infiltrator Water Technologies is a leading national provider of plastic leach field chambers and systems, septic tanks and accessories, primarily for use in residential applications. Infiltrator Water Technologies products are used in on-site septic wastewater treatment systems in the United States and Canada. International – The International segment manufactures and markets pipe and allied products in certain regions outside of the United States, including Company owned facilities in Canada, subsidiaries that distribute to Europe and the Middle East, exports and through the Company’s joint ventures with local partners in Mexico and South America. The Company’s Mexican joint venture, ADS Mexicana, primarily serves the Mexican and Central American markets, while its South American Joint Venture, Tigre-ADS, is the primary channel to serve the South American markets. The Company’s International product lines include single wall pipe, N-12 HDPE pipe, high performance PP pipe and certain geographies also sell our broad line of Allied Products & Other. Allied Products & Other – Allied Products & Other manufactures and markets products throughout the United States. Products include StormTech, Nyloplast, ARC Septic Chambers, Inserta Tee, BaySaver filters and water quality structures, Fittings, and FleXstorm. The Company maintains and serves these markets through product distribution relationships with many of the largest national and independent waterworks distributors, major national retailers as well as an extensive network of hundreds of small to medium-sized distributors across the U.S. The Company also sells through a broad variety of buying groups and co-ops in the United States. The following table sets forth reportable segment information with respect to the amount of Net sales contributed by each class of similar products for the fiscal years ended March 31: 2020 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 954,633 $ (2,030 ) $ 952,603 Infiltrator Water Technologies 211,005 (41,657 ) 169,348 International International - Pipe 108,624 — 108,624 International - Allied Products & Other 39,957 — 39,957 Total International 148,581 — 148,581 Allied Products & Other 403,273 — 403,273 Intersegment Eliminations (43,687 ) 43,687 — Total Consolidated $ 1,673,805 $ — $ 1,673,805 2019 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 868,805 $ — $ 868,805 Infiltrator Water Technologies — — — International International - Pipe 122,836 — 122,836 International - Allied Products & Other 37,766 — 37,766 Total International 160,602 — 160,602 Allied Products & Other 355,326 — 355,326 Intersegment Eliminations — — — Total Consolidated $ 1,384,733 $ — $ 1,384,733 2018 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 844,875 $ — $ 844,875 Infiltrator Water Technologies — — — International International - Pipe 119,207 — 119,207 International - Allied Products & Other 36,715 — 36,715 Total International 155,922 — 155,922 Allied Products & Other 329,557 — 329,557 Intersegment Eliminations — — — Total Consolidated $ 1,330,354 $ — $ 1,330,354 The following sets forth certain financial information attributable to the reportable segments for the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Segment adjusted gross profit Pipe $ 239,531 $ 191,002 $ 186,330 Infiltrator Water Technologies 98,245 — — International 36,999 37,191 31,725 Allied Products & Other 201,206 168,729 155,166 Intersegment Elimination (1,895 ) — — Total $ 574,086 $ 396,922 $ 373,221 Depreciation and amortization Pipe $ 46,611 $ 49,419 $ 51,236 Infiltrator Water Technologies 7,159 — — International 6,013 5,938 6,431 Allied Products & Other (a) 65,157 16,543 17,336 Total $ 124,940 $ 71,900 $ 75,003 Capital expenditures Pipe $ 33,629 $ 34,878 $ 32,393 Infiltrator Water Technologies 24,917 — — International 2,623 3,765 2,147 Allied Products & Other (a) 6,508 4,769 7,169 Total $ 67,677 $ 43,412 $ 41,709 (a) Includes depreciation and amortization and capital expenditures not allocated to a reportable segment. The amortization expense of Infiltrator Water Technologies intangible assets acquired is included in Allied Products & Other. Reconciliation of Gross Profit to Segment Adjusted Gross profit (Amounts in thousands) 2020 2019 2018 Reconciliation of Segment Adjusted Gross Profit: Total Gross Profit $ 316,479 $ 326,967 $ 302,481 Depreciation and amortization 62,225 59,164 62,113 ESOP and stock-based compensation expense 14,319 10,791 8,627 ESOP special dividend compensation 168,610 — — COVID-19 Related Expenses (a) 4,573 — — Inventory step up related to Infiltrator Water Technologies acquisition 7,880 — — Total Segment Adjusted Gross Profit $ 574,086 $ 396,922 $ 373,221 (a) Represents the Company’s pandemic pay expense included in Gross profit in connection with the Company’s response to the COVID-19 pandemic, see “Note 16. Employee Benefit Plans” for additional information. Geographic Sales and Assets Information Net sales are attributed to the geographic location based on the location of the customer. The table below represents the Net sales and long-lived asset information by geographic location for each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Net Sales North America $ 1,655,219 $ 1,366,470 $ 1,313,917 Other 18,586 18,263 16,437 Total $ 1,673,805 $ 1,384,733 $ 1,330,354 (Amounts in thousands) 2020 2019 Long-Lived Assets (a) North America $ 488,125 $ 401,276 Other 9,250 10,467 Total $ 497,375 $ 411,743 (a) For segment reporting purposes, long-lived assets include Investments in unconsolidated affiliates, Central parts and Property, plant and equipment.

Supplemental Disclosures of Cas

Supplemental Disclosures of Cash Flow Information	12 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures of Cash Flow Information	2 2 . SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION Supplemental disclosures of cash flow information for the fiscal years ended March 31 were as follows: (Amounts in thousands) 2020 2019 2018 Supplemental disclosures of cash flow information — cash paid during years: Interest $ 41,290 $ 15,679 $ 17,890 Income taxes 8,710 29,841 24,510 (Amounts in thousands) 2020 2019 2018 Supplemental disclosures of noncash investing and financing activities: Redeemable convertible preferred stock dividend $ 359 $ 134 $ 134 Purchases of plant, property, and equipment included in accounts payable 1,588 1,255 1,258 ESOP distributions in common stock 13,109 8,609 11,566 Lease obligation retired upon disposition of leased assets 799 578 636 Contribution of net accounts receivable to the South American Joint Venture — — 2,785 Payable recorded for business acquisition — — 300

Quarterly Financial Information

Quarterly Financial Information (Unaudited)	12 Months Ended
	Mar. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information (Unaudited)	2 3 . QUARTERLY FINANCIAL INFORMATION (UNAUDITED) The following tables set forth certain historical unaudited consolidated condensed quarterly financial information for each of the quarters during the years ended March 31, 2020 and 2019. In the Company’s opinion, the unaudited quarterly financial information reflects all normal and recurring accruals and adjustments necessary for a fair presentation of net income for interim periods. Fiscal 2020 For the Three Months Ended (in thousands, except per share amounts) March 31, 2020 December 31, 2019 September 30, 2019 June 30, 2019 Net sales $ 370,768 $ 393,424 $ 495,905 $ 413,708 Gross profit 108,755 123,358 146,524 (62,158 ) Net income (loss) 3,533 23,659 8,462 (227,451 ) Net income (loss) attributable to ADS 2,305 23,288 7,589 (226,356 ) Net (loss) income per share Basic (1) $ 0.01 $ 0.28 $ 0.10 $ (4.06 ) Diluted (1) $ 0.01 $ 0.28 $ 0.10 $ (4.06 ) Fiscal 2019 For the Three Months Ended (in thousands, except per share amounts) March 31, 2019 December 31, 2018 September 30, 2018 June 30, 2018 Net sales $ 272,218 $ 318,113 $ 406,555 $ 387,847 Gross profit 59,504 72,399 95,373 99,691 Net income 1,893 16,550 29,372 33,651 Net income attributable to ADS 1,010 15,812 28,670 32,280 Net income per share Basic (1) $ 0.01 $ 0.25 $ 0.45 $ 0.51 Diluted (1) $ 0.01 $ 0.25 $ 0.45 $ 0.51 (1) The earnings per share calculations for each quarter are based upon the applicable weighted average shares outstanding for each period and may not necessarily be equal to the full year share amount.

Subsequent Events

Subsequent Events	12 Months Ended
	Mar. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	2 4 . SUBSEQUENT EVENTS Dividends on Common Stock - During the first quarter of fiscal 2021, the Company declared a quarterly cash dividend of $0.09 per share of common stock. The dividend is payable on June 15, 2020 to stockholders of record at the close of business on June 1, 2020. * * * * * *

Schedule II - Consolidated Valu

Schedule II - Consolidated Valuation and Qualifying Accounts	12 Months Ended
	Mar. 31, 2020
Valuation And Qualifying Accounts [Abstract]
Schedule II - Consolidated Valuation and Qualifying Accounts	SCHEDULE II ADVANCED DRAINAGE SYSTEMS, INC. AND SUBSIDIARIES Consolidated Valuation and Qualifying Accounts for the Fiscal Years Ended March 31, 2020, 2019 and 2018 (in thousands): Allowance for Doubtful Accounts: Year ended March 31, Balance at beginning of period Charged to costs and expenses (1) Charged to other accounts (2) Deductions (3) Balance at end of period 2020 $ 7,653 $ (24 ) $ (234 ) $ (2,360 ) $ 5,035 2019 6,826 1,154 (65 ) (262 ) 7,653 2018 10,431 503 (391 ) (3,717 ) 6,826 (1) Amount for the year ended March 31, 2020 includes $0.4 million due to the Acquisition. (2) Amounts represent the impact of foreign currency translation. ( 3 ) Amounts includes the release of a $3.0 million allowance related to the South American Joint Venture capital contribution. See “Note 11. Investment in Unconsolidated Affiliates” for additional information.

Background and Summary of Sig_2

Background and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation - The consolidated financial statements include the Company, its wholly-owned subsidiaries, its majority owned subsidiaries, and variable interest entities (“VIEs”) of which the Company is the primary beneficiary. The Company uses the equity method of accounting for equity investments where it exercises significant influence but does not hold a controlling financial interest. Such investments are recorded in Other assets in the Consolidated Balance Sheets and the related equity in earnings from these investments are included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations. All intercompany balances and transactions have been eliminated in consolidation.
Estimates	Estimates - The preparation of consolidated financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingencies and liabilities at the balance sheet date and the reported amounts of revenues and expenses during the reporting period. Significant estimates include, but are not limited to, purchase accounting for the Acquisition, the allowance for doubtful accounts, valuation of inventory, useful lives of property, plant and equipment and amortizing intangible assets, determination of the proper accounting for leases, valuation of equity method investments, goodwill, intangible assets and other long-lived assets for impairment, accounting for stock-based compensation and the ESOP, valuation of the redeemable convertible preferred stock, determination of allowances for sales returns, rebates and discounts, determination of the valuation allowance, if any, on deferred tax assets, and reserves for uncertain tax positions. Management’s estimates and assumptions are evaluated on an ongoing basis and are based on historical experience, current conditions and available information. Management believes the accounting estimates are appropriate and reasonably determined; however, due to the inherent uncertainties in making these estimates, actual results could differ from those estimates.
Receivables and Allowance for Doubtful Accounts	Receivables and Allowance for Doubtful Accounts - Receivables include trade receivables, net of an allowance for doubtful accounts, and other miscellaneous receivables. Receivables at March 31, 2020 and 2019 are as follows: (Amounts in thousands) 2020 2019 Trade receivables, net $ 195,968 $ 170,887 Other miscellaneous receivables 4,060 16,104 Receivables, net $ 200,028 $ 186,991 As of March 31, 2020 and 2019, Other miscellaneous receivables includes insurance recoverables of approximately $3.2 million and $3.9 million, respectively, which has a corresponding liability recorded in Other accrued liabilities. Credit is extended to customers based on an evaluation of their financial condition and collateral is generally not required. The evaluation of the customer’s financial condition is performed to reduce the risk of loss. Accounts receivable are evaluated for collectability based on numerous factors, including the length of time individual receivables are past due, past transaction history with customers, their credit worthiness and the economic environment. This estimate is periodically adjusted when management becomes aware of a situation in which there is doubt the customer does not have the ability or intention to pay its financial obligations (e.g. bankruptcy filing).
Inventories	Inventories - Inventories are stated at the lower of cost or net realizable value. The Company’s inventories are maintained on the first-in, first-out (“FIFO”) method. Costs include the cost of acquiring materials, including in-bound freight from vendors and freight incurred for the transportation of raw materials, tooling or finished goods between the Company’s manufacturing plants and its distribution centers, direct and indirect labor, factory overhead and certain corporate overhead costs related to the production of inventory. The portion of fixed manufacturing overhead that relates to capacity in excess of our normal capacity is expensed in the period in which it is incurred and is not included in inventory. Net realizable value of inventory is established with consideration given to deterioration, obsolescence, and other factors. The Company periodically evaluates the carrying value of inventories and adjustments are made whenever necessary to reduce the carrying value to net realizable value.
Property, Plant and Equipment and Depreciation Method	Property, Plant and Equipment and Depreciation Method - Property, plant and equipment are recorded at cost less accumulated depreciation, with the exception of assets acquired through acquisitions, which are initially recorded at fair value. Equipment acquired under finance lease is recorded at the present value of the future minimum lease payments. Depreciation is computed for financial reporting purposes using the straight-line method over the estimated useful lives of the related assets or the lease term, if shorter, as follows: Years Buildings and leasehold improvements 20 to 45 or the lease term if shorter Machinery and production equipment 3 to 18 Transportation equipment 3 to 12 Costs of additions and major improvements are capitalized, whereas maintenance and repairs that do not improve or extend the life of the asset are charged to expense as incurred. When assets are retired or disposed, the cost and related accumulated depreciation are removed from the asset accounts and any resulting gain or loss is reflected in Loss on disposal of assets and costs from exit and disposal activities in our Consolidated Statements of Operations. Construction in progress is also recorded at cost and includes capitalized interest, capitalized payroll costs and related costs such as taxes and other fringe benefits.
Goodwill	Goodwill - The Company records acquisitions resulting in the consolidation of an enterprise using the acquisition method of accounting. Under this method, the Company records the assets acquired, including intangible assets that can be identified, and liabilities assumed based on their estimated fair values at the date of acquisition. The purchase price in excess of the fair value of the identifiable assets acquired and liabilities assumed is recorded as goodwill. Goodwill is reviewed annually for impairment as of March 31 or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. If the fair value of the reporting unit exceeds the carrying value of the net assets assigned to that unit, goodwill is not considered impaired and the Company is not required to perform further testing. If the carrying value of a reporting unit’s goodwill exceeds its fair value, then the Company would record an impairment loss equal to the difference. With respect to this testing, a reporting unit is a component of the Company for which discrete financial information is available and regularly reviewed by management. The fair value of goodwill is determined by considering both the income and market approach. Determining the fair value of a reporting unit is judgmental in nature and involves the use of significant estimates and assumptions. These estimates and assumptions include revenue growth rates and operating margins used to calculate projected future cash flows, risk-adjusted discount rates, future economic and market conditions, and determination of appropriate market comparison. The fair value estimates are based on assumptions management believes to be reasonable but are inherently uncertain. For the fiscal year ended March 31, 2020, the Company completed a quantitative fair value assessment for all reporting units and determined no impairment charge was required. For all other fiscal years presented, ADS completed a quantitative fair value assessment of the Canada reporting unit and determined no impairment charge was required. GAAP allows entities testing goodwill for impairment the option of performing a qualitative assessment before calculating the fair value of a reporting unit for the goodwill impairment test. If the qualitative assessment is performed, an entity is no longer required to calculate the fair value of a reporting unit unless the entity determines that, based on that assessment, it is not more likely than not that its fair value is less than its carrying amount. ADS applied the qualitative assessment to the former Domestic reporting unit for the annual impairment tests performed as of March 31, 2019 and 2018. The qualitative assessment indicated that no impairment charges were required for goodwill in the fiscal years ended March 31, 2019 and 2018.
Intangible Assets - Definite-Lived	Intangible Assets — Definite-Lived - Definite-lived intangible assets are amortized using the straight-line method or an accelerated method over their estimated useful lives and are tested for recoverability whenever events or changes in circumstances indicate that carrying amounts of the asset group may not be recoverable. Asset groups are established primarily by determining the lowest level of cash flows available. If the estimated undiscounted future cash flows are less than the carrying amounts of such assets, an impairment loss is recognized to the extent the fair value of the asset less any costs of disposition is less than the carrying amount of the asset. Determining the fair value of these assets is judgmental in nature and involves the use of significant estimates and assumptions.
Intangible Assets - Indefinite-Lived	Intangible Assets — Indefinite-Lived - Indefinite-lived intangible assets are tested for impairment annually as of March 31 or whenever events or changes in circumstances indicate the carrying value may be greater than fair value. Determining the fair value of these assets is judgmental in nature and involves the use of significant estimates and assumptions. The Company bases its fair value estimates on assumptions it believes to be reasonable, but that are inherently uncertain. To estimate the fair value of these indefinite-lived intangible assets, the Company uses an income approach, which utilizes a market derived rate of return to discount anticipated performance. An impairment loss is recognized when the estimated fair value of the intangible asset is less than the carrying value. ADS completed a quantitative fair value measurement of indefinite-lived trademarks as of March 31, 2020. The test indicated that the fair value of the indefinite-lived trademarks substantially exceeded the carrying value, indicating that no impairment existed. GAAP allows entities testing indefinite-lived intangible assets for impairment the option of performing a qualitative assessment before calculating the fair value of the indefinite-lived intangible assets for the impairment test. If the qualitative assessment is performed, an entity is no longer required to calculate the fair value of an indefinite-lived intangible assets unless the entity determines that, based on that assessment, it is more likely than not that its fair value is less than its carrying amount. ADS applied the qualitative assessment to specific trademarks for the annual impairment test s performed as of March 31, 2019 and 2018 . For the qualitative test, ADS assessed various assumptions, events and circumstances that would have affected the estimated fair value of the reporting unit as compared to its March 31, 2016 quantitative fair value measurement. The results of this assessment indicated that it is not more likely than not that the trademarks fair value is less than the reporting unit carrying value. The Company did no t incur any impairment charges for Intangible assets in the fiscal years ended March 31, 2019 and 2018 .
Other Assets	Other Assets - Other assets include operating lease right of use assets, investments in unconsolidated affiliates accounted for under the equity method, capitalized software development costs, including cloud computing costs, deposits, central parts, and other miscellaneous assets. See “Note 6. Lease” for further information on the operating lease right of use assets. The Company capitalizes development costs for internal use software. Capitalization of software development costs begins in the application development stage and ends when the asset is placed into service. The Company amortizes such costs using the straight-line method over estimated useful lives of 2 to 10 years, which is included in General and administrative expense, Selling expense or Cost of goods sold within the Consolidated Statements of Operations depending on the nature of the asset and its intended use. Central parts represent spare production equipment items which are used to replace worn or broken production equipment parts and help reduce the risk of prolonged equipment outages. The cost of central parts is amortized on a straight-line basis over estimated useful lives of 3 to 10 years. The Company evaluates its investments in unconsolidated affiliates for impairment whenever events or changes in circumstances indicate that the carrying amount might not be recoverable and recognizes an impairment loss when a decline in value below carrying value is determined to be other-than-temporary. Under these circumstances, the Company would adjust the investment down to its estimated fair value, which then becomes its new carrying value. The impairment charge is included in Equity in net loss of unconsolidated affiliates in the Consolidated Statements of Operations. Other assets as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Right of use assets - Operating leases $ 24,875 $ — Investments in unconsolidated affiliates 9,250 10,467 Capitalized software development costs, net 11,045 13,069 Deposits 3,842 2,985 Central parts 6,745 2,385 Other 13,383 8,034 Total other assets $ 69,140 $ 36,940 The following table sets forth amortization expense related to Other assets in each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Capitalized software development costs $ 3,116 $ 2,659 $ 2,156 Central parts 87 73 47 Other 85 1,419 1,688
Leases	Leases - The Company determines whether an arrangement contains a lease at inception by determining if the contract conveys the right to control the use of identified plant, property, and equipment for a period of time in exchange for consideration and other facts and circumstances as defined by ASC 842. For each lease which has an accounting lease term of greater than 12 months, the Company records the right-of-use asset and lease liability on the balance sheet. The accounting lease term includes cancellable and renewal periods which are reasonably assured. The lease liability is measured utilizing the incremental borrowing rate unless the Company can specifically determine the rate implicit in the lease. Leases are evaluated for appropriate classification as operating or financing at lease inception. For leases classified as finance leases at lease inception, the Company records a finance lease asset and lease financing obligation equal to the present value of the minimum lease payments. The finance lease right of use asset is recorded in Property, plant and equipment, net and amortized to its expected residual value at the end of the lease term using the straight-line method, and the lease financing obligation is amortized using the effective interest method over the lease term with the rental payments being allocated to principal and interest. For leases classified as operating leases, the Company records the operating lease right of use asset in other assets and operating lease obligation in other accrued liabilities and other liabilities. Operating lease rent expense over the useful life using the straight-line method. ASC 842 Adoption - The Company adopted the provisions of ASC 842 beginning on April 1, 2019 using the transition methodology in ASC 842 which does not require adjustments to comparative periods or require modified disclosures. The Company elected the transition relief practical expedient package as described in ASC 842-10-65-1. ASC 842 provides lessees with the option of electing an accounting policy, by class of underlying asset, in which the lessee may choose not to separate nonlease components from lease components. The Company elected this practical expedient for leases of certain classes of equipment, including forklifts and fleet tractors and trailers. The Company also elected the accounting policy to not recognize the right-of-use asset and lease liability for leases with an accounting lease term of twelve months or less (“Short-term leases”). The adoption of ASC 842 resulted in the recording of $13.3 million of additional lease liabilities and right-of-use assets to the beginning balance of the Company’s Consolidated Balance Sheet. Infiltrator Water Technologies adopted ASC 842 on July 31, 2019 using the same methodology and policy elections taken by the Company on April 1, 2019. The Infiltrator Water Technologies adoption of ASC 842 resulted in the recording of $11.2 million of additional lease liabilities and corresponding right-of-use assets to the beginning balance of the Company’s Consolidated Balance Sheet. At the date of adoption, ASC 842 did not have an impact on the Company’s Consolidated Statement of Operations and Consolidated Statement of Cash Flows. Nature of the Company’s Leases - The Company has operating and finance leases for plants, yards, corporate offices, tractors, trailers and other equipment. The Company’s leases have remaining terms of less than one year to 30 years. A portion of the Company’s real estate leases include an option to extend the leases for up to 5 years. The Company has included renewal options which are reasonably certain to be exercised in its right-of-use assets and lease liabilities. The Company’s lease payments are generally fixed. Certain equipment leases contain residual value guarantees that create a contingent obligation on the part of the Company to compensate the lessor if the leased asset cannot be sold for an amount in excess of a specified minimum value at the conclusion of the lease term. The calculation is based on the original cost of the transportation equipment, less lease payments made, compared to a percentage of the transportation equipment’s fair market value at the time of sale. All leased units covered by this guarantee have been classified as finance leases and a corresponding finance lease obligation was recorded. Therefore, no contingent obligation is needed. For all leases with an initial expected term of more than 12 months, the Company recorded, at the adoption date of ASC 842 or lease commencement date for leases entered into after the adoption date, a lease liability, which is the lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The Company will utilize its collateralized incremental borrowing rate commensurate to the lease term as the discount rate for its leases, unless the Company can specifically determine the lessor’s implicit rate. The incremental borrowing rate for each lease is determined based on the Company’s credit rating, adjusted for the impacts of collateral, and the lease term.
Foreign Currency Translation	Foreign Currency Translation - Assets and liabilities of foreign subsidiaries with a functional currency other than the U.S. dollar are translated into U.S. dollars at the current rate of exchange on the last day of the reporting period. Revenues and expenses are translated at a monthly average exchange rate and equity transactions are translated using either the actual exchange rate on the day of the transaction or a monthly average historical exchange rate. The South American Joint Venture operates within Argentina, which on July 1, 2018, was identified for high inflationary accounting. The Company has determined the effect of a change in the exchange rate under high inflationary accounting does not have a material effect on the Company’s results in any annual period. For the fiscal years ended March 31, 2020 and 2019, the Company’s Accumulated other comprehensive loss (“AOCL”) consisted of foreign currency translation gains and losses.
Net Sales	Net Sales - The Company generates revenue by selling pipe and related water management products primarily to distributors, retailers, buying groups and co-operative buying groups. Products are shipped predominately by the Company’s internal fleet, and the Company does not provide any additional revenue generating services after product delivery. Payment terms and conditions vary by contract. Revenue is recognized at the point in-time obligations under the terms of a contract with a customer are satisfied, which generally occurs upon the transfer of control of the promised goods. In substantially all of the Company’s contracts with customers, control is transferred to the customer upon delivery. The Company recognizes revenue in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services.
Shipping Costs	Shipping Costs - The Company incurs shipping costs to deliver products to customers using an in-house fleet or common carrier. Typically shipping costs are prepaid and included in the product price; however, in some instances, the Company bills shipping costs to customers. Shipping costs are also incurred to physically move raw materials, tooling and products between manufacturing and distribution facilities. Shipping costs to deliver products to customers for the fiscal years ended March 31, 2020, 2019, and 2018 were $149.0 million, $131.3 million, and $120.7 million, respectively, and are included in Cost of goods sold. Shipping costs billed to customers were $7.9 million, $7.7 million, and $6.3 million during 2020, 2019 and 2018, respectively, and are included in Net sales.
Stock-Based Compensation	Stock-Based Compensation - See “Note 17. Stock-Based Compensation” for information about our stock-based compensation award programs and related accounting policies. The Company has several programs for stock-based payments to employees and directors, including stock options and restricted stock. Stock-based compensation expense is recorded in General and administrative expenses, Selling expenses and Cost of goods sold in the Consolidated Statements of Operations. The Company recognized stock-based compensation expense in the following line items on the Consolidated Statements of Operations for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Component of income before income taxes: Cost of goods sold $ 897 $ 317 $ 179 Selling expenses 426 180 105 General and administrative expenses 10,946 6,035 6,837 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121 The following table summarizes stock-based compensation expense by award type for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Stock-based compensation expense: Equity-classified stock options 2,554 2,550 4,148 Restricted stock 3,807 2,064 1,741 Performance-based restricted stock units 4,682 869 — Non-employee director 1,226 1,049 1,232 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121 The following table summarizes the assumptions used in estimating the fair value of stock options: 2020 2019 2018 Common stock price $27.44 - $41.85 $25.75 - $27.99 $19.35 - $22.95 Expected stock price volatility 30.1% - 30.9% 30.3% - 31.1% 32.1% - 35.6% Risk-free interest rate 1.4% - 2.3% 2.9% - 3.1% 1.9% - 2.2% Weighted-average expected option life (years) 6.0 6.0 5.6 - 6.0 Dividend yield 0.9% - 1.3% 1.1% - 1.2% 1.1% - 1.5% 2000 and 2013 Stock Options Plans Equity classified stock option awards are measured based on the grant date estimated fair value of each award. Compensation expense for stock options is recognized on a straight-line basis over the employee’s requisite service period, which is generally the vesting period of the grant. The Company estimates the fair value of stock options using a Black-Scholes option-pricing model. 2000 Plan - The Company’s 2000 stock option plan (“2000 Plan”) provided for the issuance of statutory and non-statutory stock options to management based upon the discretion of the Board of Directors. The plan generally provided for grants with the exercise price equal to fair value on the date of grant, which vest in three equal annual amounts beginning in year five and expire after approximately 10 years from issuance. The Company had no shares available for grant under the 2000 Plan as of March 31, 2020. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 82 $ 14.64 4.3 Granted — — — Exercised (8 ) 13.87 — Forfeited (3 ) 15.74 — Outstanding at end of year 71 14.69 3.4 Vested at end of year 37 13.73 2.8 Unvested at end of year 34 15.74 4.0 Fair value of options granted during the year $ — All outstanding options are expected to vest. The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 54 $ 6.76 Granted — — Vested (17 ) 8.72 Forfeitures (3 ) 8.72 Unvested at end of year 34 $ 8.72 As of March 31, 2020, there was a total of $0.1 million of unrecognized compensation expense related to unvested stock option awards under the 2000 plan that will be recognized as an expense as the awards vest over the remaining weighted average service period of 1.3 years. During the fiscal year end March 31, 2020, 0.1 million shares vested. No options vested during fiscal years ended March 31, 2019 and 2018. No options were granted during the fiscal years ended March 31, 2020, 2019, and 2018. The aggregate intrinsic value for options outstanding and currently exercisable as of March 31, 20 20 was $ million and $ million, respectively. The total intrinsic value of options exercised during the fiscal years ended March 31, 2020, 2019, and 2018 were $ million, $ million and $ 0.5 million, respectively. 2013 Plan - The Company’s 2013 stock option plan (“2013 Plan”) provided for the issuance of non-statutory common stock options to management subject to the Board’s discretion. The plan generally provided for grants with the exercise price equal to fair value on the date of grant. The grants generally vest in three to five equal annual amounts beginning in year one and expire after approximately 10 years from issuance. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 1,120 $ 16.81 4.9 Granted — — — Exercised (555 ) 14.11 — Forfeited — — — Outstanding at end of year 565 19.45 4.7 Vested at end of year 542 19.25 4.6 Unvested at end of year 23 24.12 6.0 Fair value of options granted during the year $ — All outstanding options are expected to vest. The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 121 $ 7.68 Granted — — Vested (98 ) 7.80 Forfeited — — Unvested at end of year 23 $ 7.20 As of March 31, 2020, there was a total of $0.1 million of unrecognized compensation expense related to unvested stock option awards under the 2013 Plan that will be recognized as an expense as the awards vest over the remaining weighted average service period of 0.9 years. The aggregate intrinsic value for options outstanding and currently exercisable as of March 31, 2020 was $5.6 million and $5.5 million, respectively. The total fair value of options that vested during the fiscal years ended March 31, 2020, 2019, and 2018 were $0.8 million, $2.6 million, and $4.7 million, respectively. The total intrinsic value of options exercised during the fiscal year ended March 31, 2020 was $13.2 million. 2008 Restricted Stock Plan On September 16, 2008, the Board of Directors adopted the restricted stock plan, which provided for the issuance of restricted stock awards to certain key employees. The restricted stock generally vest ratably over a five-year Employees with restricted stock have the right to dividends on the shares awarded (vested and unvested) in addition to voting rights on non-forfeited shares. The fair value of restricted stock is based on the fair value of the Company’s common stock. Compensation expense is recognized on a straight-line basis over the employee’s requisite service period, which is generally the vesting period of the grant. The Company had no shares available for grant under this plan as of March 31, 2020. The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 44 $ 24.17 Granted — — Vested (37 ) 24.18 Forfeited (1 ) 24.20 Unvested at end of year 6 $ 24.10 The Company expects all restricted stock grants to vest. At March 31, 2020, there was approximately $0.1 million of unrecognized compensation expense related to the restricted stock that will be recognized over the weighted average remaining service period of 1.0 years. 2017 Omnibus Plan On May 24, 2017, the Board of Directors approved the 2017 Omnibus Incentive Plan (the “2017 Incentive Plan”) which was approved by the Company’s stockholders on July 17, 2017. The 2017 Incentive Plan provides for the issuance of a maximum of 3.5 million shares of the Company’s common stock for awards made thereunder, which awards may consist of stock options, restricted stock, restricted stock units, stock appreciation rights, phantom stock, cash-based awards, performance awards (which may take the form of performance cash, performance units or performance shares) or other stock-based awards. The Company had approximately 1.8 million shares available for awards as of March 31, 2020. The 2017 Incentive Plan replaces the 2000 Incentive Stock Option Plan, 2008 Restricted Stock Plan, 2013 Stock Option Plan, and 2014 Non-Employee Director Compensation Plan (the “Prior Plans”) and no further grants will be made under the prior plans. The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 457 $ 23.19 8.9 Granted 336 27.51 — Exercised (8 ) 25.75 — Forfeited — — — Outstanding at end of year 785 25.01 8.4 Vested at end of year 212 22.04 7.7 Unvested at end of year 573 26.11 8.7 Fair value of options granted during the year 8.02 The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 388 $ 7.19 Granted 336 8.02 Vested (151 ) 7.01 Forfeited — — Unvested at end of year 573 $ 7.73 The aggregate intrinsic value for options outstanding and exercisable as of March 31, 2020 was $3.5 million and $1.6 million, respectively. There were 0.1 million options that were exercised during the fiscal year ended March 31, 2020. The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 172 $ 25.02 Granted 308 31.96 Vested (90 ) 25.63 Forfeited (2 ) 27.13 Unvested at end of year 388 $ 30.38 At March 31, 2020, there was approximately $8.2 million of unrecognized compensation expense related to the restricted stock that will be recognized over the weighted average remaining service period of 2.1 years. The total fair value of restricted stock that vested during fiscal year ended March 31, 2020 and 2019 was $2.3 million and $2.0 million, respectively. During the fiscal year ended March 31, 2018, no restricted stock vested. The information about the performance units granted under the 2017 Omnibus Plan is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 115 $ 25.85 Granted 274 33.27 Vested — — Forfeited — — Unvested at end of year 389 $ 31.07 At March 31, 2020, there was approximately $9.6 million of unrecognized compensation expense related to the performance units that will be recognized over the weighted average remaining service period of 1.9 years. For the performance units, 50% of the award is based upon the achievement of certain levels of Return on Invested Capital for the performance period and 50% is based upon the achievement of certain levels of Free cash flow for the performance period. During fiscal year 2020, the Company modified the achievement levels of the awards due to the Acquisition of Infiltrator Water Technologies. The modification did not result in any incremental compensation expense. The performance units have a 3-year performance period from April 1, 2019 through March 31, 2022. The performance units, and any accrued dividend equivalents, will be settled in shares of the Company’s common stock, if the applicable performance and service conditions are satisfied. In addition to the performance units based on ADS performance, the Company issued performance units based on the achievements of other performance targets. During fiscal year 2020, the Company granted 0.1 million units with a grant date fair value of $ million, subject to achieving predetermined synergies of the now consolidated legacy ADS business and Infiltrator Water Technologies. The Company further granted 0.1 million units with a grant date fair value of $ 2.7 million, subject to performance conditions of the Infiltrator Water Technologies reportable segment. For the performance units based on the Infiltrator Water Technologies reportable segment, 75% of the award is based upon the achievement of certain levels of Infiltrator Water Technologies Adjusted EBITDA for the performance period and 25% is based upon the achievement of certain levels of Infiltrator Water Technologies Free c ash f low for the performance period . These two performance unit grants have a 3-year performance period from August 1, 2019 through March 31, 2022 . During the fiscal year ended March 31, 20 20 and 2019 , the weighted average gran t date fair value of performance units granted was $ 33.27 and $ 25.84 , respectively . During the fiscal year ended March 31, 20 20 and 2019 , the total fair value of performance units that vested was $ 0.0 million and $ 0.1 million. During the fiscal year ended March 31, 2018, no performance units vested
Advertising	Advertising - The Company expenses advertising costs as incurred. Advertising costs are recorded in Selling expenses in the Consolidated Statements of Operations. The total advertising costs were $4.9 million, $3.8 million, and $4.1 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively
Self-Insurance	Self-Insurance - The Company is self-insured for short term disability and medical coverage it provides for substantially all eligible employees. The Company is self-insured for medical claims up to the individual and aggregate stop-loss coverage limits. The Company accrues for claims incurred but not reported based on an estimate of future claims related to events that occurred prior to the fiscal year end if it has not met the aggregate stop-loss coverage limit. Amounts expensed totaled $50.3 million, $42.4 million, and $41.3 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively, of which employees contributed $7.9 million, $6.7 million, and $5.9 million, respectively ADS is also self-insured for various other general insurance programs to the extent of the applicable deductible limits on the Company’s insurance coverage. These programs include primarily automobile, general liability and employment practices coverage with a deductible of $0.5 million per occurrence or claim incurred. Amounts expensed during the period, including an estimate for claims incurred but not reported at year end, were $2.5 million, $2.3 million, and $2.2 million, for the years ended March 31, 2020, 2019, and 2018, respectively. ADS is also self-insured for workers’ compensation insurance with stop-loss coverage for claims that exceed $0.3 million per incident up to the respective state statutory limits. Amounts expensed, including an estimate for claims incurred but not reported, were $3.0 million, $2.8 million, and $1.3 million for the fiscal years ended March 31, 2020, 2019, and 2018, respectively.
Income Taxes	Income Taxes - Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized and represent the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. They are measured using the enacted tax rates expected to apply to taxable income in the years in which the related temporary differences are expected to be recovered or settled. Valuation allowances are established against deferred tax assets when it is more likely than not that the realization of those deferred tax assets will not occur. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. The deferred income tax provision represents the change during the reporting period in the deferred tax assets and deferred tax liabilities. Penalties and interest recorded on income taxes payable are recorded as part of Income tax expense. The Company determines whether an uncertain tax position is more likely than not to be sustained upon examination, including resolution of any related appeals or litigation process, based upon the technical merits of the position. For tax positions meeting the more likely than not threshold, the tax amount recognized in the financial statements is the largest amount of tax benefit that has a greater than 50% likelihood of being realized upon ultimate settlement with the relevant taxing authority.
Fair Values	Fair Values - The fair value framework requires the categorization of assets and liabilities into three levels based upon assumptions (inputs) used to price the assets or liabilities. Level 1 provides the most reliable measure of fair value, whereas Level 3 generally requires significant management judgment. ADS’s policy for determining when transfers between levels have occurred is to use the actual date of the event or change in circumstances that caused the transfer.
Concentrations of Risk	Concentrations of Risk - The Company has a large, active customer base of approximately twenty thousand customers with two customers, Ferguson Enterprises and Core and Main, each representing more than 10% of annual net sales. Financial instruments that potentially subject the Company to a concentration of credit risk consist principally of Receivables. The Company provides its products to customers based on an evaluation of the customers’ financial condition, generally without requiring collateral. Exposure to losses on Receivables is principally dependent on each customer’s financial condition. The Company performs ongoing credit evaluations of its customers. The Company monitors the exposure for credit losses and maintains allowances for anticipated losses. Concentrations of credit risk with respect to Receivables are limited due to the large number of customers comprising the Company’s customer base and their dispersion across many different geographies. One customer, Ferguson Enterprises, accounted for approximately 18.2 % and 19.1 % of Receivables at March 31, 2020 and 2019 , respectively .
Derivatives	Derivatives - The Company recognizes derivative instruments as either assets or liabilities and measure those instruments at fair value. ADS uses interest rate swaps, commodity options in the form of collars and swaps, and foreign currency forward contracts to manage various exposures to interest rate, commodity price, and exchange rate fluctuations. These instruments do not qualify for hedge accounting treatment. For the interest rate swap executed on June 28, 2017, gains and losses resulting from the difference between the spot rate and applicable base rate was recorded in Interest expense. For commodity options in the form of collars and swaps, and foreign currency forward contracts, gains and losses from contract settlements and changes in fair value of the derivative instruments are recognized in Derivative losses (gains) and other expense (income), net in the Consolidated Statements of Operations. The Company’s policy is to present all derivative balances on a gross basis. The Company also has forward purchase agreements in place with certain resin suppliers for virgin polyethylene resin. The agreements specify a fixed amount of virgin resin material to be purchased at a fixed price for a given period of time in quantities the Company will use in the normal course of business, and therefore, qualify as normal purchase contracts. The cost of such resin is recognized in Cost of goods sold in the Consolidated Statements of Operations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Recently Adopted Accounting Guidance Leases - In February 2016, the Financial Accounting Standards Board (the “FASB”) issued an accounting standard update (“ASU”) which amends the guidance for leases (“ASC 842”). This standard contains principles that will require an entity to recognize most leases on the balance sheet by recording a right-of-use asset and a lease liability, unless the lease is a short-term lease that has an accounting lease term of twelve months or less. The standard also contains other changes to the current lease guidance that may result in changes to how entities determine which contractual arrangements qualify as a lease, the accounting for executory costs, such as property taxes and insurance, as well as which lease origination costs will be capitalizable. In July 2018, the FASB amended ASC 842 to provide another transition method, allowing a cumulative effect adjustment to the opening balance of retained earnings during the period of adoption. The Company adopted these standards effective April 1, 2019 using the transition method in the July 2018 ASU which does not require adjustments to comparative periods or require modified disclosures for those periods and includes transition relief practical expedients. See “Note 6. Leases” for further information on the adoption of the new lease ASUs. Hedge Accounting - In August 2017, the FASB issued an ASU which expanded an entity’s ability to apply hedge accounting for non-financial and financial risk components and provided a simplified approach for fair value hedging of interest rate risk. The standard also refined how entities assess hedge effectiveness. The Company adopted this standard effective April 1, 2019. The new standard did not have an impact on the Consolidated Financial Statements. Recent Accounting Guidance Not Yet Adopted Measurement of Credit Losses - In June 2016, the FASB issued an ASU which provides amended guidance on the measurement of credit losses on financial instruments, including trade receivables. This standard requires the use of an impairment model referred to as the current expected credit loss model. This standard is effective for fiscal years beginning after December 15, 2019, including interim periods within those years, and early adoption is permitted for fiscal years beginning after December 15, 2018. The Company will adopt this standard effective April 1, 2020. The Company’s adoption of the standard will not have a material impact on the Company’s Consolidated Financial Statements. Reference Rate Reform - In March 2020, the FASB issued an ASU that provides optional expedients and exceptions related to financial reporting impacts related to the expected market transition from LIBOR to another reference rates. The amendments are effective on March 12, 2020 and an entity may elect to adopt prospectively through December 31, 2022. The Company is currently evaluating the impact of this standard on the Consolidated Financial Statements. Income Taxes – In December 2019, the FASB issued an ASU to simplify the accounting for income taxes by removing certain exceptions to the general principles in ASC 740, and improve the comparability of financial statements. The amendments in this ASU are effective for fiscal years beginning after December 15, 2020, and early adoption is permitted. The Company is currently evaluating the impact of this standard on the Consolidated Financial Statements. Except for the pronouncements described above, there have been no new accounting pronouncements issued or adopted since the filing of the fiscal 2019 Form 10-K that have significance, or potential significance, to the Consolidated Financial Statements.

Background and Summary of Sig_3

Background and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2020
Accounting Policies [Abstract]
Summary of Receivables	Receivables and Allowance for Doubtful Accounts - Receivables include trade receivables, net of an allowance for doubtful accounts, and other miscellaneous receivables. Receivables at March 31, 2020 and 2019 are as follows: (Amounts in thousands) 2020 2019 Trade receivables, net $ 195,968 $ 170,887 Other miscellaneous receivables 4,060 16,104 Receivables, net $ 200,028 $ 186,991
Estimated Useful Lives of Related Assets	Depreciation is computed for financial reporting purposes using the straight-line method over the estimated useful lives of the related assets or the lease term, if shorter, as follows: Years Buildings and leasehold improvements 20 to 45 or the lease term if shorter Machinery and production equipment 3 to 18 Transportation equipment 3 to 12
Other Assets	Other assets as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Right of use assets - Operating leases $ 24,875 $ — Investments in unconsolidated affiliates 9,250 10,467 Capitalized software development costs, net 11,045 13,069 Deposits 3,842 2,985 Central parts 6,745 2,385 Other 13,383 8,034 Total other assets $ 69,140 $ 36,940
Amortization Expense Related to Other Assets	The following table sets forth amortization expense related to Other assets in each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Capitalized software development costs $ 3,116 $ 2,659 $ 2,156 Central parts 87 73 47 Other 85 1,419 1,688

Loss on Disposal of Assets an_2

Loss on Disposal of Assets and Costs from Exit and Disposal Activities (Tables)	12 Months Ended
	Mar. 31, 2020
Discontinued Operations And Disposal Groups [Abstract]
Summary of Loss on Disposal of Assets and Costs from Exit and Disposal Activities	The following table summarizes the activity included in loss on disposal of assets and costs from exit and disposal activities recorded during the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Accelerated depreciation $ — $ 430 $ 3,759 Plant severance — 131 2,041 Headcount reduction — 306 4,133 Product optimization — 283 1,351 Other restructuring activities — 475 159 Total 2018 Restructuring Plan activities $ — $ 1,625 $ 11,443 Acquisition related severance and other costs 2,557 $ — $ — Loss on other disposals and partial disposals of property, plant and equipment 2,781 2,022 3,560 Total loss on disposal of assets and costs from exit and disposal activities $ 5,338 $ 3,647 $ 15,003
Schedule of Reconciliation of Restructuring Liability	A reconciliation of the beginning and ending amounts of restructuring liability related to the 2018 Restructuring Plan for the fiscal years ended March 31, 2020 and 2019 (Amounts in thousands) 2020 2019 Balance at beginning of year $ 1,696 $ 3,901 Expenses — 1,625 Non-cash expenses — (713 ) Payments (1,122 ) (3,117 ) Balance at end of year $ 574 $ 1,696

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Mar. 31, 2020
Revenue From Contract With Customer [Abstract]
Schedule of Contract Asset and Liability	The following table presents the balance of the Company’s contract asset and liability as of March 31, 2020 and April 1, 2019: March 31, 2020 April 1, 2019 (In thousands) Contract asset - product returns $ 594 $ 646 Refund liability 1,458 1,372

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Mar. 31, 2020
Business Acquisition [Line Items]
Summary of Identifiable Intangible Assets	The following table presents the amortization expense and weighted average amortization period for definite-lived intangible assets at March 31, 2020: Amortization expense (in thousands) 2020 2019 2018 Weighted Average Amortization Period (in years) Developed technology $ 12,517 $ 2,517 $ 2,517 10.0 Customer relationships 36,093 3,546 3,633 19.8 Patents 522 546 591 12.0 Non-compete and other contractual agreements 22 22 104 — Trademarks and tradenames 7,856 1,249 1,223 19.6
IWT [Member]
Business Acquisition [Line Items]
Summary of Consideration Transferred and Preliminary Purchase Price Allocation of Assets Acquired and Liabilities Assumed	The following table summarizes the consideration transferred and the preliminary purchase price allocation of the assets acquired and liabilities assumed. (Amounts in thousands) Initial Amount Adjustments to Purchase Price Adjustments to Property, Plant and Equipment Adjustments to Intangible Assets Tax Adjustments Updated Amount Cash $ 57,375 $ — $ — $ — $ — $ 57,375 Total current assets, excluding cash 75,847 — — — — 75,847 Property, plant and equipment 98,860 — (6,575 ) — — 92,285 Goodwill 567,034 704 6,575 (100,000 ) 21,528 495,841 Intangible assets, net 475,000 — — 100,000 — 575,000 Other assets 14,366 — — — — 14,366 Total current liabilities (22,756 ) — — — 931 (21,825 ) Deferred tax liabilities (109,926 ) — — — (22,459 ) (132,385 ) Other liabilities (9,274 ) — — — — (9,274 ) Total fair value of consideration transferred $ 1,146,526 $ 704 $ — $ — $ — $ 1,147,230
Summary of Identifiable Intangible Assets	The identifiable intangible assets recorded in connection with the closing of the Acquisition are based on valuations including customer relationships, patents and developed technology, and tradename and trademarks totaling $575.0 million. Customer relationships are amortized using an accelerated method over an estimated useful life of 20 years. Patents and developed technology and tradename and trademarks are on a straight-line basis over the respective useful lives of 10 and 20 years. (Amounts in thousands) Preliminary fair value Estimated useful lives Customer relationships $ 360,000 20 years Patents and developed technology 150,000 10 years Tradename and trademarks 65,000 20 years Total identifiable intangible assets $ 575,000
Summary of Unaudited Pro Forma Information	The unaudited pro forma information for the fiscal year ended March 31, 2020 presented below includes the effects of the Acquisition as if it had been consummated as of April 1, 2017, with adjustments to give effect to pro forma events that are directly attributable to the Acquisition. (Amounts in thousands) 2020 2019 2018 Net sales $ 1,760,208 $ 1,608,450 $ 1,520,571 Net income (loss) attributable to ADS (145,244 ) 27,411 (33,606 )

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Mar. 31, 2020
Property Plant And Equipment [Abstract]
Schedule of Property, Plant and Equipment	Property, plant and equipment, net as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Land, buildings and improvements $ 253,379 $ 199,810 Machinery and production equipment 631,932 560,858 Transportation equipment 208,037 221,721 Construction in progress 19,925 19,749 Total cost 1,113,273 1,002,138 Less: accumulated depreciation (631,893 ) (603,247 ) Property, plant and equipment, net $ 481,380 $ 398,891
Depreciation Expense Related to Property, Plant and Equipment	The following table sets forth depreciation expense related to Property, plant and equipment in each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Depreciation expense (inclusive of leased assets depreciation) (1) $ 64,642 $ 59,869 $ 63,044 (1) Depreciation expense does not include accelerated depreciation expense from the 2018 Restructuring plan. See “Note 2. Loss on Disposal of Assets and Costs from Exit and Disposal Activities” for additional discussion.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Mar. 31, 2020
Leases [Abstract]
Schedule of Components of Lease Cost	Lease Cost - The components of lease cost for the year ended March 31, 2020 was: (Amounts in thousands) Income Statement Classification 2020 Operating lease cost Operating lease cost Cost of goods sold $ 5,548 Operating lease cost General and administrative 1,204 Short-term lease cost Cost of goods sold 2,393 Total operating lease cost $ 9,145 Finance lease cost Amortization of right-of-use assets Cost of goods sold 17,059 Amortization of right-of-use assets General and administrative 2,543 Interest on lease liabilities Interest expense 4,344 Total finance lease cost $ 23,946
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases for the fiscal year ended March 31, 2020 was as follows: (Amounts in thousands) 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows from operating leases $ 6,572 Operating cash flows from finance leases 4,675 Financing cash flows from finance leases 27,119 Right-of-use assets obtained in exchange for lease obligations: Operating leases 10,529 Finance leases (a) 5,078 (a) The Company acquired $27.6 million and $26.8 million of property, plant and equipment under finance leases in the fiscal years ended March 31, 2019 and March 31, 2018, respectively.
Schedule of Supplemental Balance Sheet Information Related to Leases	Supplemental balance sheet information related to leases as of March 31, 2020 was as follows: (Amounts in thousands) Balance Sheet Classification 2020 Operating leases Right-of-use assets Other assets $ 24,875 Current lease liabilities Other accrued liabilities 7,757 Non-current lease liabilities Other liabilities 17,173 Total operating lease liabilities $ 24,930 Finance leases Right-of-use assets Property, plant and equipment 90,756 Current lease liabilities Current maturities of finance lease obligations 20,382 Non-current lease liabilities Long-term finance lease obligations 44,501 Total finance lease liabilities $ 64,883 Weighted average lease term Operating leases 6.97 Finance leases 10.72 Weighted average discount rate Operating leases 3.57 % Finance leases 5.36 %
Schedule of Future Minimum Lease Payments on Rolling Twelve-month Basis under Operating and Finance Leases	The following is a schedule by year of future minimum lease payments on a rolling twelve-month basis under operating and finance leases and the present value of the net minimum lease payments as of March 31, 2020: (Amounts in thousands) Operating Leases Finance Leases Year 1 $ 8,511 $ 23,492 Year 2 5,717 19,478 Year 3 3,839 13,182 Year 4 2,768 8,355 Year 5 2,041 4,736 Thereafter 6,075 4,722 Total minimum lease payments $ 28,951 $ 73,965 Less: amount representing interest 4,021 9,082 Present value of net minimum lease payments $ 24,930 $ 64,883
Summary of Leased Assets Included in Property, Plant and Equipment	Leased assets included in Property, plant and equipment as of the fiscal year ended March 31, 2019 consisted of the following: (Amounts in thousands) 2019 Buildings and improvements $ 5,357 Machinery and equipment 220,279 Total cost 225,636 Less: accumulated depreciation (114,856 ) Leased assets in Property, plant and equipment, net $ 110,780
Schedule of Interest and Depreciation Expense Related to Capital Leases	The following sets forth the interest and depreciation expense related to capital leases recorded in each fiscal year ended March 31: (Amounts in thousands) 2019 2018 Lease interest expense $ 5,215 $ 4,086 Depreciation of leased assets 19,155 18,511
Schedule of Contractual Obligations for Capital and Operating Leases	As of March 31, 2019, total contractual obligations for capital and operating leases were as follows: (Amounts in thousands) Operating Leases Finance Leases Year 1 $ 4,159 $ 26,604 Year 2 2,924 22,507 Year 3 1,814 18,064 Year 4 690 11,721 Year 5 325 7,143 Thereafter 2,236 8,198 Total minimum lease payments $ 12,148 $ 94,237 Less: amount representing interest — 9,565 Present value of net minimum lease payments $ 12,148 $ 84,672

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Mar. 31, 2020
Inventory Disclosure [Abstract]
Schedule of Inventories	Inventories as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Raw materials $ 66,524 $ 47,910 Finished goods 215,874 216,630 Total Inventories $ 282,398 $ 264,540

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Mar. 31, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Carrying Amount of Goodwill by Reportable Segment	Goodwill - The carrying amount of goodwill by reportable segment is as follows: As Previously Reported (Amounts in thousands) Domestic International Pipe Infiltrator Water Technologies Allied Products & Other Total Balance at March 31, 2018 $ 92,105 $ 10,912 $ — $ — $ — $ 103,017 Currency translation — (379 ) — — — (379 ) Balance at March 31, 2019 $ 92,105 $ 10,533 $ — $ — $ — $ 102,638 Reallocation due to change in segments (92,105 ) — 57,663 — 34,442 — Acquisition — — — 495,841 — 495,841 Currency translation — (660 ) — — — (660 ) Balance at March 31, 2020 $ — $ 9,873 $ 57,663 $ 495,841 $ 34,442 $ 597,819
Summary of Intangible Assets	Intangible Assets – Intangible assets as of March 31, 2020 and 2019 consisted of the following: 2020 2019 (Amounts in thousands) Gross Intangible Accumulated Amortization Net Intangible Gross Intangible Accumulated Amortization Net Intangible Definite-lived intangible assets Developed technology $ 177,579 $ (32,437 ) $ 145,142 $ 27,580 $ (19,922 ) $ 7,658 Customer relationships 377,742 (47,051 ) 330,691 29,851 (23,000 ) 6,851 Patents 8,951 (6,419 ) 2,532 8,313 (5,561 ) 2,752 Non-compete and other contractual agreements — — — 155 (138 ) 17 Trademarks and tradenames 69,847 (4,736 ) 65,111 15,978 (7,968 ) 8,010 Total definite lived intangible assets 634,119 (90,643 ) 543,476 81,877 (56,589 ) 25,288 Indefinite-lived intangible assets (a) Trademarks 11,862 — 11,862 11,889 — 11,889 Total Intangible assets $ 645,981 $ (90,643 ) $ 555,338 $ 93,766 $ (56,589 ) $ 37,177
Summary of Identifiable Intangible Assets	The following table presents the amortization expense and weighted average amortization period for definite-lived intangible assets at March 31, 2020: Amortization expense (in thousands) 2020 2019 2018 Weighted Average Amortization Period (in years) Developed technology $ 12,517 $ 2,517 $ 2,517 10.0 Customer relationships 36,093 3,546 3,633 19.8 Patents 522 546 591 12.0 Non-compete and other contractual agreements 22 22 104 — Trademarks and tradenames 7,856 1,249 1,223 19.6
Future Intangible Asset Amortization Expense	The following table presents the future intangible asset amortization expense based on existing intangible assets at March 31, 2020: Fiscal Year (Amounts in thousands) 2021 2022 2023 2024 2025 Thereafter Total Amortization expense $ 71,705 $ 61,305 $ 52,328 $ 48,200 $ 44,872 $ 265,066 $ 543,476

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	12 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Assets and Liabilities Carried at Fair Value	The assets, liabilities and mezzanine equity carried at fair value as of the fiscal years ended March 31 were as follows: March 31, 2020 (Amounts in thousands) Total Level 1 Level 2 Level 3 Assets: Derivative assets — diesel fuel contracts $ 36 $ — $ 36 $ — Total assets at fair value on a recurring basis $ 36 $ — $ 36 $ — Liabilities: Derivative liability - diesel fuel contracts $ 2,228 $ — $ 2,228 $ — Contingent consideration for acquisitions (a) 60 — — 60 Total liabilities at fair value on a recurring basis $ 2,288 $ — $ 2,228 $ 60 March 31, 2019 (Amounts in thousands) Total Level 1 Level 2 Level 3 Assets: Derivative assets — diesel fuel contracts $ 189 $ — $ 189 $ — Interest rate swaps 1,088 — 1,088 — Total assets at fair value on a recurring basis $ 1,277 $ — $ 1,277 $ — Liabilities: Derivative liability - diesel fuel contracts $ 283 $ — $ 283 $ — Foreign exchange forward contracts 60 — 60 — Contingent consideration for acquisitions 203 — — 203 Total liabilities at fair value on a recurring basis $ 546 $ — $ 343 $ 203 (a) The fair value of the contingent consideration for acquisitions is based on management’s estimate of contractual payments based on future product certifications obtained.
Summary of Changes in Fair Value of Recurring Fair Value Measurements Using Unobservable Inputs	Changes in the fair value of recurring fair value measurements using significant unobservable inputs (Level 3) for the fiscal years ended March 31, 2020 and 2019 were as follows: Contingent consideration Balance at March 31, 2018 $ 578 Asset acquisition $ 40 Change in fair value (6 ) Payments of contingent consideration liability (409 ) Balance at March 31, 2019 $ 203 Payments of contingent consideration liability (143 ) Balance at March 31, 2020 $ 60

Investment in Affiliates (Table

Investment in Affiliates (Tables)	12 Months Ended
	Mar. 31, 2020
ADS Mexicana [Member]
Assets and Liabilities of Joint Ventures	The table below includes the assets and liabilities of ADS Mexicana that are consolidated as of March 31, 2020 and 2019. The balances exclude intercompany transactions that are eliminated upon consolidation. (Amounts in thousands) 2020 2019 Assets Current assets $ 18,357 $ 18,683 Property, plant and equipment, net 12,438 17,054 Other noncurrent assets 1,317 1,396 Total assets $ 32,112 $ 37,133 Liabilities Current liabilities $ 6,350 $ 6,581 Noncurrent liabilities 1,131 1,264 Total liabilities $ 7,481 $ 7,845

Debt (Tables)

Debt (Tables)	12 Months Ended
	Mar. 31, 2020
Debt Disclosure [Abstract]
Long-Term Debt	Long-term debt as of the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Term Loan Facility $ 648,250 $ — Senior Notes 350,000 — Revolving Credit Facility 100,000 — PNC Credit Agreement — 134,400 Prudential Senior Notes — 100,000 Equipment financing 1,492 2,427 Total 1,099,742 236,827 Unamortized debt issuance costs (2,419 ) (2,293 ) Current maturities (7,955 ) (25,932 ) Long-term debt obligations $ 1,089,368 $ 208,602
Maturities of Long-term Debt (Excluding Interest and Deferred Financing Costs)	Maturities of long-term debt (excluding interest and deferred financing costs) as of March 31, 2020 are summarized below: Fiscal Years Ending March 31, (Amounts in thousands) 2021 2022 2023 2024 2025 Thereafter Total Principal maturities $ 7,955 $ 7,532 $ 7,000 $ 7,000 $ 107,000 $ 963,255 $ 1,099,742

Derivative Transactions (Tables

Derivative Transactions (Tables)	12 Months Ended
	Mar. 31, 2020
Fair Value Disclosures [Abstract]
Summary of Fair Values for Various Derivatives	A summary of the fair values for the various derivatives at March 31, 2020 and 2019 is presented below: 2020 Assets Liabilities (Amounts in thousands) Receivables Other assets Other accrued liabilities Other liabilities Diesel fuel option collars and swaps $ 21 $ 15 $ (2,000 ) $ (228 ) 2019 Assets Liabilities (Amounts in thousands) Receivables Other assets Other accrued liabilities Other liabilities Diesel fuel option collars and swaps $ 127 $ 62 $ (201 ) $ (82 ) Foreign exchange forward contracts — — (60 ) — Interest rate swaps 566 522 — —
Schedule of Cash Settlements and Net Losses and Net (Gains) on Mark-to-Market Adjustments for Changes in Fair Value of Derivative Contracts	The Company recorded net losses and net (gains) on mark-to-market adjustments for changes in the fair value of derivative contracts as well as net losses and net (gains) on the settlement of derivative contracts as follows: Net Unrealized Mark to Market Losses (Gains) (Amounts in thousands) 2020 2019 2018 Interest rate swaps $ 1,029 $ 1,712 $ (2,801 ) Foreign exchange forward contracts — 60 — Diesel fuel option collars 2,099 574 (443 ) Total net unrealized mark to market losses (gains) $ 3,128 $ 2,346 $ (3,244 ) Net Realized Losses (Gains) (Amounts in thousands) 2020 2019 2018 Interest rate swaps $ 378 $ (329 ) $ — Foreign exchange forward contracts 102 (163 ) — Diesel fuel option collars 357 (698 ) (476 ) Total net realized losses (gains) $ 837 $ (1,190 ) $ (476 )

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Mar. 31, 2020
Redeemable Convertible Preferred Stock [Member]
Summarized Cash and Stock Dividends on Allocated Redeemable Convertible Preferred Stock	During fiscal year ended March 31, 2020, the Board of Directors approved a special cash dividend of $1.00 per share. See “Note 19. Net Income Per Share and Stockholders’ Equity” for additional information. Cash and stock dividends on allocated Redeemable convertible preferred stock for the fiscal years ended March 31, 2020 and 2019, respectively, are summarized in the following table. (Amounts in thousands) 2020 2019 Quarterly cash dividends $ 10,840 $ 1,903 Annual cash dividends 7 10 Total cash dividends $ 10,847 $ 1,913 Annual stock dividend 359 134 Annual cash dividend 7 10 Total ESOP required dividends $ 366 $ 144 Allocated shares 18,756 7,392 Required dividend per share 0.0195 0.0195 Required dividends $ 366 $ 144

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2020
Summary of Stock-based Compensation Expense	The Company recognized stock-based compensation expense in the following line items on the Consolidated Statements of Operations for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Component of income before income taxes: Cost of goods sold $ 897 $ 317 $ 179 Selling expenses 426 180 105 General and administrative expenses 10,946 6,035 6,837 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121 The following table summarizes stock-based compensation expense by award type for the fiscal years ended March 31, 2020, 2019, and 2018: (Amounts in thousands) 2020 2019 2018 Stock-based compensation expense: Equity-classified stock options 2,554 2,550 4,148 Restricted stock 3,807 2,064 1,741 Performance-based restricted stock units 4,682 869 — Non-employee director 1,226 1,049 1,232 Total stock-based compensation expense $ 12,269 $ 6,532 $ 7,121
Summary of Assumption Used in Estimate Fair Value of Stock Options	The following table summarizes the assumptions used in estimating the fair value of stock options: 2020 2019 2018 Common stock price $27.44 - $41.85 $25.75 - $27.99 $19.35 - $22.95 Expected stock price volatility 30.1% - 30.9% 30.3% - 31.1% 32.1% - 35.6% Risk-free interest rate 1.4% - 2.3% 2.9% - 3.1% 1.9% - 2.2% Weighted-average expected option life (years) 6.0 6.0 5.6 - 6.0 Dividend yield 0.9% - 1.3% 1.1% - 1.2% 1.1% - 1.5%
2000 Stock Option Plan [Member]
Schedule of Stock Option Activity	The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 82 $ 14.64 4.3 Granted — — — Exercised (8 ) 13.87 — Forfeited (3 ) 15.74 — Outstanding at end of year 71 14.69 3.4 Vested at end of year 37 13.73 2.8 Unvested at end of year 34 15.74 4.0 Fair value of options granted during the year $ —
Schedule of Unvested Stock Option Grants	The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 54 $ 6.76 Granted — — Vested (17 ) 8.72 Forfeitures (3 ) 8.72 Unvested at end of year 34 $ 8.72
2013 Stock Option Plan [Member]
Schedule of Stock Option Activity	The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 1,120 $ 16.81 4.9 Granted — — — Exercised (555 ) 14.11 — Forfeited — — — Outstanding at end of year 565 19.45 4.7 Vested at end of year 542 19.25 4.6 Unvested at end of year 23 24.12 6.0 Fair value of options granted during the year $ —
Schedule of Unvested Stock Option Grants	The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 121 $ 7.68 Granted — — Vested (98 ) 7.80 Forfeited — — Unvested at end of year 23 $ 7.20
2008 Restricted Stock Plan [Member]
Summary of Unvested Restricted Stock Grants	The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 44 $ 24.17 Granted — — Vested (37 ) 24.18 Forfeited (1 ) 24.20 Unvested at end of year 6 $ 24.10
2017 Omnibus Plan [Member]
Schedule of Stock Option Activity	The stock option activity for the fiscal year ended March 31, 2020 is summarized as follows: (Share amounts in thousands) Number of Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Outstanding at beginning of year 457 $ 23.19 8.9 Granted 336 27.51 — Exercised (8 ) 25.75 — Forfeited — — — Outstanding at end of year 785 25.01 8.4 Vested at end of year 212 22.04 7.7 Unvested at end of year 573 26.11 8.7 Fair value of options granted during the year 8.02
Schedule of Unvested Stock Option Grants	The following table summarizes information about the unvested stock option grants as of the fiscal year ended March 31, 2020: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 388 $ 7.19 Granted 336 8.02 Vested (151 ) 7.01 Forfeited — — Unvested at end of year 573 $ 7.73
Summary of Unvested Restricted Stock Grants	The information about the unvested restricted stock grants as of March 31, 2020 is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 172 $ 25.02 Granted 308 31.96 Vested (90 ) 25.63 Forfeited (2 ) 27.13 Unvested at end of year 388 $ 30.38
Summary of Performance Units Granted	The information about the performance units granted under the 2017 Omnibus Plan is as follows: (Share amounts in thousands) Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 115 $ 25.85 Granted 274 33.27 Vested — — Forfeited — — Unvested at end of year 389 $ 31.07

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2020
Income Tax Disclosure [Abstract]
Components of Income before Income Taxes	The components of Income before income taxes for the fiscal years ended March 31 are as follows: (Amounts in thousands) 2020 2019 2018 United States $ (186,209 ) $ 103,559 $ 72,109 Foreign 6,595 8,051 4,833 Total $ (179,614 ) $ 111,610 $ 76,942
Components of Income Tax Expense	The components of Income tax expense for the fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 2018 Current: Federal $ 10,867 $ 11,575 $ 17,107 State and local 4,655 3,998 3,541 Foreign 1,546 2,050 2,242 Total current tax expense 17,068 17,623 22,890 Deferred: Federal 210 11,745 (11,236 ) State and local (1,228 ) 1,795 (55 ) Foreign (1,958 ) (1,114 ) (188 ) Total deferred tax expense (benefit) (2,976 ) 12,426 (11,479 ) Total Income tax expense $ 14,092 $ 30,049 $ 11,411
Effective Tax Rate Varied from Statutory Federal Income Tax Rate	For the fiscal years ended March 31, the effective tax rate varied from the statutory Federal income tax rate as a result of the following factors: 2020 2019 2018 Federal statutory rate 21.0 % 21.0 % 31.5 % ESOP stock appreciation, ESOP dividends and special dividend (a) (30.3 ) 3.2 5.4 Effect of tax rate of foreign subsidiaries 0.6 (0.3 ) 0.7 State and local taxes—net of federal income tax benefit (1.7 ) 4.6 3.6 Uncertain tax position change 1.2 (1.3 ) 0.3 Impact of tax reform — — (19.4 ) Equity-based compensation 1.1 (0.4 ) 0.5 Return to provision - federal and state 0.3 (0.2 ) (5.0 ) Qualified production activity deduction — — (2.5 ) Executive compensation (0.8 ) 1.1 0.1 Net operating losses 1.9 — — Credits and incentives 0.7 (1.0 ) (0.5 ) Other (1.9 ) 0.2 0.1 Effective rate (7.9 )% 26.9 % 14.8 % (a) This includes the special dividend paid in the first quarter of fiscal 2020 that resulted in $246.8 million in additional stock-based compensation. Of the total stock-based compensation expense and dividends paid, approximately $242.9 million related to non-deductible stock appreciation and deductible dividends. This decreased the effective tax rate by 28.4%. See “Note 19. Net Income Per Share and Stockholders’ Equity” for additional information.
Schedule of Deferred Tax Assets and Liabilities	The tax effect of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at March 31 were comprised of: (Amounts in thousands) 2020 2019 Deferred tax assets: Receivable and other allowances $ 1,122 $ 1,546 Inventory 2,065 3,217 Stock-based compensation 2,770 3,186 Worker’s compensation 2,317 2,063 Net operating loss and credit carryforwards 2,059 152 Operating lease liabilities 6,160 - Other 5,562 4,673 Total deferred tax assets 22,055 14,837 Less: valuation allowance (941 ) (269 ) Total net deferred tax assets 21,114 14,568 Deferred tax liabilities: Intangible assets 121,276 2,512 Property, plant and equipment 63,649 52,218 Operating lease assets 6,147 - Goodwill 4,527 4,078 Other 600 1,385 Total deferred tax liabilities 196,199 60,193 Net deferred tax liability $ 175,085 $ 45,625 Net deferred tax assets and liabilities are included in Other assets and Deferred tax liabilities, respectively, on the Consolidated Balance Sheets. The related balances at March 31 were as follows: (Amounts in thousands) 2020 2019 Net non-current deferred tax assets $ 531 $ 338 Net non-current deferred tax liabilities 175,616 45,963
Reconciliation of Beginning and Ending Balance of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amounts of unrecognized tax benefits for the years ended March 31, 2020, 2019, and 2018 is as follows: (Amounts in thousands) 2020 2019 2018 Balance at beginning of year $ 5,681 $ 7,593 $ 6,196 Tax positions taken in current year — 164 81 Decreases in tax positions for prior years (1,398 ) (198 ) — Increases in tax positions for prior years 1,907 136 5,108 Settlements (124 ) (200 ) — Lapse of statute of limitations (2,589 ) (1,595 ) (3,940 ) Foreign translation adjustment (134 ) (219 ) 148 Balance at end of year $ 3,343 $ 5,681 $ 7,593

Net Income Per Share and Stoc_2

Net Income Per Share and Stockholders' Equity (Tables)	12 Months Ended
	Mar. 31, 2020
Net Income Per Share And Stockholders Equity [Abstract]
Summary of Net Income Per Share	The following table presents information necessary to calculate net income per share for the fiscal years ended March 31, 2020, 2019, and 2018, as well as potentially dilutive securities excluded from the weighted average number of diluted common shares outstanding because their inclusion would have been anti-dilutive: (Amounts in thousands, except per share data) 2020 2019 2017 NET INCOME PER SHARE — BASIC: Net (loss) income attributable to ADS $ (193,174 ) $ 77,772 $ 62,007 Adjustment for: Dividends paid to redeemable convertible preferred stockholders (11,206 ) (2,047 ) (1,858 ) Dividends paid to unvested restricted stockholders (338 ) (69 ) (49 ) Net income available to common stockholders and participating securities (204,718 ) 75,656 60,100 Undistributed income allocated to participating securities — (5,474 ) (4,514 ) Net income available to common stockholders — Basic (204,718 ) 70,182 55,586 Weighted average number of common shares outstanding — Basic 63,820 57,025 55,696 Net (loss) income per common share — Basic $ (3.21 ) $ 1.23 $ 1.00 NET INCOME PER SHARE — DILUTED: Net income available to common stockholders — Diluted (204,718 ) 70,182 55,586 Weighted average number of common shares outstanding — Basic 63,820 57,025 55,696 Assumed restricted stock - nonparticipating — 39 — Assumed exercise of stock options — 547 638 Weighted average number of common shares outstanding — Diluted 63,820 57,611 56,334 Net (loss) income per common share — Diluted $ (3.21 ) $ 1.22 $ 0.99 Potentially dilutive securities excluded as anti- dilutive 14,449 5,966 6,167

Other Accrued Liabilities (Tabl

Other Accrued Liabilities (Tables)	12 Months Ended
	Mar. 31, 2020
Payables And Accruals [Abstract]
Schedule of Other Accrued Liabilities	Other accrued liabilities as of fiscal years ended March 31 consisted of the following: (Amounts in thousands) 2020 2019 Accrued compensation and benefits (1) $ 33,215 $ 18,108 Accrued rebate liability (2) 14,479 12,313 Lease liability - Operating leases 7,757 — Self-insurance accruals 12,486 11,697 Other 33,179 19,783 Total accrued liabilities $ 101,116 $ 61,901 (1) Accrued compensation and benefits is primarily comprised of accrued payroll, bonuses and commissions. (2) Accrued rebate liability represents the Company’s estimated rebates to be paid to customers.

Business Segment Information (T

Business Segment Information (Tables)	12 Months Ended
	Mar. 31, 2020
Segment Reporting [Abstract]
Schedule of Revenue from Reportable Segments by Product Type	The following table sets forth reportable segment information with respect to the amount of Net sales contributed by each class of similar products for the fiscal years ended March 31: 2020 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 954,633 $ (2,030 ) $ 952,603 Infiltrator Water Technologies 211,005 (41,657 ) 169,348 International International - Pipe 108,624 — 108,624 International - Allied Products & Other 39,957 — 39,957 Total International 148,581 — 148,581 Allied Products & Other 403,273 — 403,273 Intersegment Eliminations (43,687 ) 43,687 — Total Consolidated $ 1,673,805 $ — $ 1,673,805 2019 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 868,805 $ — $ 868,805 Infiltrator Water Technologies — — — International International - Pipe 122,836 — 122,836 International - Allied Products & Other 37,766 — 37,766 Total International 160,602 — 160,602 Allied Products & Other 355,326 — 355,326 Intersegment Eliminations — — — Total Consolidated $ 1,384,733 $ — $ 1,384,733 2018 (Amounts in thousands) Net Sales Intersegment Net Sales Net Sales from External Customers Pipe $ 844,875 $ — $ 844,875 Infiltrator Water Technologies — — — International International - Pipe 119,207 — 119,207 International - Allied Products & Other 36,715 — 36,715 Total International 155,922 — 155,922 Allied Products & Other 329,557 — 329,557 Intersegment Eliminations — — — Total Consolidated $ 1,330,354 $ — $ 1,330,354
Schedule of Financial Information Attributable to Reportable Segments	The following sets forth certain financial information attributable to the reportable segments for the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Segment adjusted gross profit Pipe $ 239,531 $ 191,002 $ 186,330 Infiltrator Water Technologies 98,245 — — International 36,999 37,191 31,725 Allied Products & Other 201,206 168,729 155,166 Intersegment Elimination (1,895 ) — — Total $ 574,086 $ 396,922 $ 373,221 Depreciation and amortization Pipe $ 46,611 $ 49,419 $ 51,236 Infiltrator Water Technologies 7,159 — — International 6,013 5,938 6,431 Allied Products & Other (a) 65,157 16,543 17,336 Total $ 124,940 $ 71,900 $ 75,003 Capital expenditures Pipe $ 33,629 $ 34,878 $ 32,393 Infiltrator Water Technologies 24,917 — — International 2,623 3,765 2,147 Allied Products & Other (a) 6,508 4,769 7,169 Total $ 67,677 $ 43,412 $ 41,709 (a) Includes depreciation and amortization and capital expenditures not allocated to a reportable segment. The amortization expense of Infiltrator Water Technologies intangible assets acquired is included in Allied Products & Other.
Reconciliation of Gross Profit to Segment Adjusted Gross Profit	Reconciliation of Gross Profit to Segment Adjusted Gross profit (Amounts in thousands) 2020 2019 2018 Reconciliation of Segment Adjusted Gross Profit: Total Gross Profit $ 316,479 $ 326,967 $ 302,481 Depreciation and amortization 62,225 59,164 62,113 ESOP and stock-based compensation expense 14,319 10,791 8,627 ESOP special dividend compensation 168,610 — — COVID-19 Related Expenses (a) 4,573 — — Inventory step up related to Infiltrator Water Technologies acquisition 7,880 — — Total Segment Adjusted Gross Profit $ 574,086 $ 396,922 $ 373,221 (a) Represents the Company’s pandemic pay expense included in Gross profit in connection with the Company’s response to the COVID-19 pandemic, see “Note 16. Employee Benefit Plans” for additional information.
Net Sales and Long-Lived Asset by Geographic Location	Geographic Sales and Assets Information Net sales are attributed to the geographic location based on the location of the customer. The table below represents the Net sales and long-lived asset information by geographic location for each of the fiscal years ended March 31: (Amounts in thousands) 2020 2019 2018 Net Sales North America $ 1,655,219 $ 1,366,470 $ 1,313,917 Other 18,586 18,263 16,437 Total $ 1,673,805 $ 1,384,733 $ 1,330,354 (Amounts in thousands) 2020 2019 Long-Lived Assets (a) North America $ 488,125 $ 401,276 Other 9,250 10,467 Total $ 497,375 $ 411,743 (a) For segment reporting purposes, long-lived assets include Investments in unconsolidated affiliates, Central parts and Property, plant and equipment.

Supplemental Disclosures of C_2

Supplemental Disclosures of Cash Flow Information (Tables)	12 Months Ended
	Mar. 31, 2020
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures Cash Flow Information	Supplemental disclosures of cash flow information for the fiscal years ended March 31 were as follows: (Amounts in thousands) 2020 2019 2018 Supplemental disclosures of cash flow information — cash paid during years: Interest $ 41,290 $ 15,679 $ 17,890 Income taxes 8,710 29,841 24,510 (Amounts in thousands) 2020 2019 2018 Supplemental disclosures of noncash investing and financing activities: Redeemable convertible preferred stock dividend $ 359 $ 134 $ 134 Purchases of plant, property, and equipment included in accounts payable 1,588 1,255 1,258 ESOP distributions in common stock 13,109 8,609 11,566 Lease obligation retired upon disposition of leased assets 799 578 636 Contribution of net accounts receivable to the South American Joint Venture — — 2,785 Payable recorded for business acquisition — — 300

Quarterly Financial Informati_2

Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Mar. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Information	The following tables set forth certain historical unaudited consolidated condensed quarterly financial information for each of the quarters during the years ended March 31, 2020 and 2019. Fiscal 2020 For the Three Months Ended (in thousands, except per share amounts) March 31, 2020 December 31, 2019 September 30, 2019 June 30, 2019 Net sales $ 370,768 $ 393,424 $ 495,905 $ 413,708 Gross profit 108,755 123,358 146,524 (62,158 ) Net income (loss) 3,533 23,659 8,462 (227,451 ) Net income (loss) attributable to ADS 2,305 23,288 7,589 (226,356 ) Net (loss) income per share Basic (1) $ 0.01 $ 0.28 $ 0.10 $ (4.06 ) Diluted (1) $ 0.01 $ 0.28 $ 0.10 $ (4.06 ) Fiscal 2019 For the Three Months Ended (in thousands, except per share amounts) March 31, 2019 December 31, 2018 September 30, 2018 June 30, 2018 Net sales $ 272,218 $ 318,113 $ 406,555 $ 387,847 Gross profit 59,504 72,399 95,373 99,691 Net income 1,893 16,550 29,372 33,651 Net income attributable to ADS 1,010 15,812 28,670 32,280 Net income per share Basic (1) $ 0.01 $ 0.25 $ 0.45 $ 0.51 Diluted (1) $ 0.01 $ 0.25 $ 0.45 $ 0.51 (1) The earnings per share calculations for each quarter are based upon the applicable weighted average shares outstanding for each period and may not necessarily be equal to the full year share amount.

Background and Summary of Sig_4

Background and Summary of Significant Accounting Policies - Additional Information (Detail)	Jul. 31, 2019	Mar. 31, 2020USD ($)SegmentCustomer	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | Segment		3
Impairment charges for goodwill			$ 0	$ 0
Impairment charges for intangible assets			0	0
Advertising costs		$ 4,900,000	3,800,000	4,100,000
Life, accidental death and dismemberment and medical coverage		50,300,000	42,400,000	41,300,000
Self insurance plan employees contribution		7,900,000	6,700,000	5,900,000
Total claims expense, self insurance		$ 3,000,000	$ 2,800,000	$ 1,300,000
Minimum likelihood percentage of tax benefit to be realized upon settlement		50.00%
Sales Revenue, Net [Member] | Ferguson Enterprises and HD Supply Waterworks [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Number of customers in the customer base | Customer		20,000
Concentration risk description		The Company has a large, active customer base of approximately twenty thousand customers with two customers, Ferguson Enterprises and Core and Main, each representing more than 10% of annual net sales.
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Ferguson Enterprises and HD Supply Waterworks [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		24.30%	25.40%	25.40%
Accounts Receivable [Member] | Customer Concentration Risk [Member] | Ferguson Enterprises [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Concentration risk percentage		18.20%	19.10%
Other General Insurance Programs [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Claims per occurrence		$ 500,000
Total claims expense, self insurance		2,500,000	$ 2,300,000	$ 2,200,000
Shipping and Handling [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Shipping costs		149,000,000	131,300,000	120,700,000
Shipping and Handling [Member] | Sales [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Shipping costs		$ 7,900,000	7,700,000	$ 6,300,000
Minimum [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Capitalized software development costs estimated useful lives		2 years
Central parts estimated useful lives		3 years
Claims per incident		$ 300,000
Maximum [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Capitalized software development costs estimated useful lives		10 years
Central parts estimated useful lives		10 years
Other Miscellaneous Receivables [Member] | Other Accrued Liabilities [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Insurance recoverables		$ 3,200,000	$ 3,900,000
IWT [Member]
Schedule Of Organization And Summary Of Significant Accounting Policies [Line Items]
Agreement and Plan of Merger date	Jul. 31, 2019	Jul. 31, 2019

Background and Summary of Sig_5

Background and Summary of Significant Accounting Policies - Summary of Receivables (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	$ 200,028	$ 186,991
Trade Receivables, Net [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	195,968	170,887
Other Miscellaneous Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, net	$ 4,060	$ 16,104

Background and Summary of Sig_6

Background and Summary of Significant Accounting Policies - Estimated Useful Lives of Related Assets (Detail)	12 Months Ended
	Mar. 31, 2020
Buildings and Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	20 to 45 or the lease term if shorter
Machinery and Production Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Machinery and Production Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	18 years
Transportation Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	3 years
Transportation Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives	12 years

Background and Summary of Sig_7

Background and Summary of Significant Accounting Policies - Other assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Other Assets Noncurrent [Abstract]
Right of use assets - Operating leases	$ 24,875
Investments in unconsolidated affiliates	9,250	$ 10,467
Capitalized software development costs, net	11,045	13,069
Deposits	3,842	2,985
Central parts	6,745	2,385
Other	13,383	8,034
Total other assets	$ 69,140	$ 36,940

Background and Summary of Sig_8

Background and Summary of Significant Accounting Policies - Amortization Expense Related to Other Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Adjustment For Amortization [Abstract]
Capitalized software development costs	$ 3,116	$ 2,659	$ 2,156
Central parts	87	73	47
Other	$ 85	$ 1,419	$ 1,688

Loss on Disposal of Assets an_3

Loss on Disposal of Assets and Costs from Exit and Disposal Activities - Additional Information (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)Facility	Mar. 31, 2018USD ($)Facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of manufacturing facilities closed | Facility		1	4
Restructuring plan activities		$ 1,625	$ 11,443
Net loss on disposition of the equipment	$ 2,781	2,022	3,560
Other Accrued Liabilities and Other Liabilities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Severance liability related to restructuring plan	$ 100	600
2018 Restructuring Plan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring plan activities		1,625
Pipe Segment [Member] | 2018 Restructuring Plan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring plan activities		1,200	11,000
International Segment [Member] | 2018 Restructuring Plan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring plan activities		$ 400	$ 400

Loss on Disposal of Assets an_4

Loss on Disposal of Assets and Costs from Exit and Disposal Activities - Summary of Loss on Disposal of Assets and Costs from Exit and Disposal Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Discontinued Operations And Disposal Groups [Abstract]
Accelerated depreciation		$ 430	$ 3,759
Plant severance		131	2,041
Headcount reduction		306	4,133
Product optimization		283	1,351
Other restructuring activities		475	159
Total 2018 Restructuring Plan activities		1,625	11,443
Acquisition related severance and other costs	$ 2,557
Loss on other disposals and partial disposals of property, plant and equipment	2,781	2,022	3,560
Total loss on disposal of assets and costs from exit and disposal activities	$ 5,338	$ 3,647	$ 15,003

Loss on Disposal of Assets an_5

Loss on Disposal of Assets and Costs from Exit and Disposal Activities - Schedule of Reconciliation of Restructuring Liability (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expenses		$ 1,625	$ 11,443
2018 Restructuring Plan [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Balance at beginning of year	$ 1,696	3,901
Expenses		1,625
Non-cash expenses		(713)
Payments	(1,122)	(3,117)
Balance at end of year	$ 574	$ 1,696	$ 3,901

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Apr. 01, 2018
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Receivables	$ 200,028	$ 186,991
Other current assets	$ 9,552	$ 6,091
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue Initial Application Period Cumulative Effect Transition [Line Items]
Receivables			$ (600)
Other current assets			$ 600

Revenue Recognition - Schedule

Revenue Recognition - Schedule of Contract Asset and Liability (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Apr. 01, 2019
Contract With Customer Asset And Liability [Abstract]
Contract asset - product returns	$ 594	$ 646
Refund liability	$ 1,458	$ 1,372

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 31, 2019	Aug. 01, 2017	Dec. 31, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Goodwill				$ 597,819	$ 102,638	$ 103,017
BaySaver, purchase price					$ 8,821
BaySaver [Member]
Business Acquisition [Line Items]
BaySaver, purchase price			$ 8,800
Non-cash adjustment to deferred taxes			$ 400
Company's ownership percentage			35.00%
Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible asset, useful life				19 years 9 months 18 days
Tradename and Trademarks [Member]
Business Acquisition [Line Items]
Intangible asset, useful life				19 years 7 months 6 days
IWT [Member]
Business Acquisition [Line Items]
Agreement and Plan of Merger date	Jul. 31, 2019			Jul. 31, 2019
Total fair value of consideration transferred	$ 1,147,200
Amount payable to acquire	6,000
Amount receivable from acquire	6,600
Goodwill	495,800
Deferred tax liabilities	132,400			$ 132,400
Step up of GAAP basis for fair market valuations	82,300
Deferred tax liabilities, acquired	50,100
Transaction costs related to Acquisition				22,900
Estimates transaction cost including tax				7,300
Intangible assets	$ 575,000
Net sales to external customers of acquired entity included in consolidated statements of operations				169,300
Earnings from operations of acquired entity included in consolidated statements of operations				$ 8,200
IWT [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible asset, useful life	20 years
IWT [Member] | Patents and Developed Technology [Member]
Business Acquisition [Line Items]
Intangible asset, useful life	10 years
IWT [Member] | Tradename and Trademarks [Member]
Business Acquisition [Line Items]
Intangible asset, useful life	20 years
IWT [Member] | Intangible Assets [Member]
Business Acquisition [Line Items]
Step up of GAAP basis for fair market valuations	$ 80,200
Duraslot, Inc [Member]
Business Acquisition [Line Items]
Goodwill		$ 2,100
Date of acquisition of business				Aug. 1, 2017
Acquisition of business		$ 2,300

Acquisitions - Summary of Consi

Acquisitions - Summary of Consideration Transferred and Preliminary Purchase Price Allocation of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	8 Months Ended
	Mar. 31, 2020	Jul. 31, 2019	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Goodwill	$ 597,819		$ 102,638	$ 103,017
IWT [Member]
Business Acquisition [Line Items]
Cash	57,375	$ 57,375
Total current assets, excluding cash	75,847	75,847
Property, plant and equipment	92,285	98,860
Goodwill	495,841	567,034
Intangible assets, net	575,000	475,000
Other assets	14,366	14,366
Total current liabilities	(21,825)	(22,756)
Deferred tax liabilities	(132,385)	(109,926)
Other liabilities	(9,274)	(9,274)
Total fair value of consideration transferred	1,147,230	$ 1,146,526
Adjustments to Property, Plant and Equipment	(6,575)
Goodwill, Increase to Purchase Price	704
Goodwill, Tax Adjustments	21,528
Adjustments to Intangible Assets	100,000
Total current liabilities, Tax Adjustments	931
Tax Adjustments	(22,459)
Increase to Purchase price	$ 704

Acquisitions - Summary of Ident

Acquisitions - Summary of Identifiable Intangible Assets (Detail) - USD ($) $ in Thousands	Jul. 31, 2019	Mar. 31, 2020
Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible asset, useful life		19 years 9 months 18 days
Tradename and Trademarks [Member]
Business Acquisition [Line Items]
Intangible asset, useful life		19 years 7 months 6 days
IWT [Member]
Business Acquisition [Line Items]
Total identifiable intangible assets, Preliminary fair value	$ 575,000
IWT [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Total identifiable intangible assets, Preliminary fair value	$ 360,000
Intangible asset, useful life	20 years
IWT [Member] | Patents and Developed Technology [Member]
Business Acquisition [Line Items]
Total identifiable intangible assets, Preliminary fair value	$ 150,000
Intangible asset, useful life	10 years
IWT [Member] | Tradename and Trademarks [Member]
Business Acquisition [Line Items]
Total identifiable intangible assets, Preliminary fair value	$ 65,000
Intangible asset, useful life	20 years

Acquisitions - Summary of Unaud

Acquisitions - Summary of Unaudited Pro Forma Information (Detail) - IWT [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Net sales	$ 1,760,208	$ 1,608,450	$ 1,520,571
Net income (loss) attributable to ADS	$ (145,244)	$ 27,411	$ (33,606)

Property, Plant, and Equipment

Property, Plant, and Equipment - Schedule of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Construction in progress	$ 19,925	$ 19,749
Property, plant and equipment, gross	1,113,273	1,002,138
Less: accumulated depreciation	(631,893)	(603,247)
Property, plant and equipment, net	481,380	398,891
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	253,379	199,810
Machinery and Production Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	631,932	560,858
Transportation Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 208,037	$ 221,721

Property, Plant, and Equipmen_2

Property, Plant, and Equipment - Depreciation Expense Related to Property, Plant and Equipment (Detail) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Property Plant And Equipment [Abstract]
Depreciation expense (inclusive of leased assets depreciation)	[1]	$ 64,642	$ 59,869	$ 63,044
[1]	Depreciation expense does not include accelerated depreciation expense from the 2018 Restructuring plan. See “Note 2. Loss on Disposal of Assets and Costs from Exit and Disposal Activities” for additional discussion.

Leases - Additional Information

Leases - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Apr. 01, 2019
Minimum [Member]
Lessee Lease Description [Line Items]
Leases remaining term	1 year
Maximum [Member]
Lessee Lease Description [Line Items]
Leases remaining term	30 years
Maximum [Member] | Real Estate Leases [Member]
Lessee Lease Description [Line Items]
Leases options to extend	5 years
ASC 842 Adoption [Member]
Lessee Lease Description [Line Items]
Additional lease liabilities		$ 13.3
Right-of-use assets		$ 13.3
Infiltrator Water Technologies [Member] | ASC 842 Adoption [Member]
Lessee Lease Description [Line Items]
Additional lease liabilities	$ 11.2
Right-of-use assets	$ 11.2

Leases - Schedule of Components

Leases - Schedule of Components of Lease Cost (Detail) $ in Thousands	12 Months Ended
	Mar. 31, 2020USD ($)
Operating lease cost
Short-term lease cost	$ 2,393
Total operating lease cost	9,145
Finance lease cost
Total finance lease cost	23,946
Cost of Goods Sold [Member]
Operating lease cost
Operating lease cost	5,548
Finance lease cost
Amortization of right-of-use assets	17,059
General and Administrative [Member]
Operating lease cost
Operating lease cost	1,204
Finance lease cost
Amortization of right-of-use assets	2,543
Interest Expense [Member]
Finance lease cost
Interest on lease liabilities	$ 4,344

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 6,572
Operating cash flows from finance leases	4,675
Financing cash flows from finance leases	27,119	$ 24,284	$ 24,214
Right-of-use assets obtained in exchange for lease obligations:
Operating leases	10,529
Finance leases	$ 5,078

Leases - Schedule of Suppleme_2

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Financial leases, Right-of-use assets	$ 90,756	$ 27,600	$ 26,800
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet

Leases - Schedule of Suppleme_3

Leases - Schedule of Supplemental Balance Sheet Information Related to Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Operating leases
Right-of-use assets	$ 24,875
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:OtherAssetsNoncurrent
Current lease liabilities	$ 7,757
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:OtherAccruedLiabilitiesCurrent
Non-current lease liabilities	$ 17,173
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	us-gaap:OtherLiabilitiesNoncurrent
Total operating lease liabilities	$ 24,930
Finance leases
Right-of-use assets	$ 90,756	$ 27,600	$ 26,800
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet	us-gaap:PropertyPlantAndEquipmentNet
Current lease liabilities	$ 20,382	$ 23,117
Non-current lease liabilities	44,501	$ 61,555
Total finance lease liabilities	$ 64,883
Weighted average lease term
Operating leases	6 years 11 months 19 days
Finance leases	10 years 8 months 19 days
Weighted average discount rate
Operating leases	3.57%
Finance leases	5.36%

Leases - Schedule of Future Min

Leases - Schedule of Future Minimum Lease Payments on Rolling Twelve-month Basis under Operating and Finance Leases (Detail) $ in Thousands	Mar. 31, 2020USD ($)
Operating Leases
Year 1	$ 8,511
Year 2	5,717
Year 3	3,839
Year 4	2,768
Year 5	2,041
Thereafter	6,075
Total minimum lease payments	28,951
Less: amount representing interest	4,021
Present value of net minimum lease payments	24,930
Finance Leases
Year 1	23,492
Year 2	19,478
Year 3	13,182
Year 4	8,355
Year 5	4,736
Thereafter	4,722
Total minimum lease payments	73,965
Less: amount representing interest	9,082
Present value of net minimum lease payments	$ 64,883

Leases - Summary of Leased Asse

Leases - Summary of Leased Assets Included in Property, Plant and Equipment (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Capital Leased Assets [Line Items]
Total cost	$ 225,636
Less: accumulated depreciation	(114,856)
Leased assets in Property, plant and equipment, net	110,780
Buildings and Improvements [Member]
Capital Leased Assets [Line Items]
Total cost	5,357
Machinery and Equipment [Member]
Capital Leased Assets [Line Items]
Total cost	$ 220,279

Leases - Schedule of Interest a

Leases - Schedule of Interest and Depreciation Expense Related to Capital Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Leases [Abstract]
Lease interest expense	$ 5,215	$ 4,086
Depreciation of leased assets	$ 19,155	$ 18,511

Leases - Schedule of Contractua

Leases - Schedule of Contractual Obligations for Capital and Operating Leases (Detail) $ in Thousands	Mar. 31, 2019USD ($)
Operating Leases
Year 1	$ 4,159
Year 2	2,924
Year 3	1,814
Year 4	690
Year 5	325
Thereafter	2,236
Total minimum lease payments	12,148
Present value of net minimum lease payments	12,148
Finance Leases
Year 1	26,604
Year 2	22,507
Year 3	18,064
Year 4	11,721
Year 5	7,143
Thereafter	8,198
Total minimum lease payments	94,237
Less: amount representing interest	9,565
Present value of net minimum lease payments	$ 84,672

Inventories - Schedule of Inven

Inventories - Schedule of Inventories (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 66,524	$ 47,910
Finished goods	215,874	216,630
Total Inventories	$ 282,398	$ 264,540

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($)	Mar. 31, 2020	Mar. 31, 2019
Inventory Disclosure [Abstract]
Work-in-process inventories	$ 0	$ 0
General and administrative cost in inventory	38,800,000	29,400,000
General and administrative cost remained in inventory	$ 8,600,000	$ 8,200,000

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Carrying Amount of Goodwill by Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Goodwill [Line Items]
Beginning balance	$ 102,638	$ 103,017
Acquisition	495,841
Currency translation	(660)	(379)
Ending balance	597,819	102,638
Pipe [Member]
Goodwill [Line Items]
Reallocation due to change in segments	57,663
Ending balance	57,663
Infiltrator Water Technologies [Member]
Goodwill [Line Items]
Acquisition	495,841
Ending balance	495,841
Allied Products & Other [Member]
Goodwill [Line Items]
Reallocation due to change in segments	34,442
Ending balance	34,442
Domestic [Member]
Goodwill [Line Items]
Beginning balance	92,105	92,105
Reallocation due to change in segments	(92,105)
Ending balance		92,105
International [Member]
Goodwill [Line Items]
Beginning balance	10,533	10,912
Currency translation	(660)	(379)
Ending balance	$ 9,873	$ 10,533

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Summary of Intangible Assets (Detail) - USD ($) $ in Thousands		Mar. 31, 2020	Mar. 31, 2019
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible		$ 634,119	$ 81,877
Accumulated Amortization		(90,643)	(56,589)
Net Intangible		543,476	25,288
Intangible Assets, Gross		645,981	93,766
Intangible assets, net		555,338	37,177
Trademarks [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Indefinite-Lived Intangible Assets	[1]	11,862	11,889
Developed Technology [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible		177,579	27,580
Accumulated Amortization		(32,437)	(19,922)
Net Intangible		145,142	7,658
Customer Relationships [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible		377,742	29,851
Accumulated Amortization		(47,051)	(23,000)
Net Intangible		330,691	6,851
Patents [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible		8,951	8,313
Accumulated Amortization		(6,419)	(5,561)
Net Intangible		2,532	2,752
Non-compete and Other Contractual Agreements [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible			155
Accumulated Amortization			(138)
Net Intangible			17
Trademarks and Tradenames [Member]
Finite And Indefinite Lived Intangible Assets [Line Items]
Gross Intangible		69,847	15,978
Accumulated Amortization		(4,736)	(7,968)
Net Intangible		$ 65,111	$ 8,010
[1]	Indefinite-lived intangible assets decreased as a result of foreign currency translation

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Schedule of Amortization Expense and Weighted Average Amortization Period for Definite-Lived Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 57,010	$ 7,880	$ 8,068
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 12,517	2,517	2,517
Weighted average amortization period	10 years
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 36,093	3,546	3,633
Weighted average amortization period	19 years 9 months 18 days
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 522	546	591
Weighted average amortization period	12 years
Non-compete and Other Contractual Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 22	22	104
Trademarks and Tradenames [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense	$ 7,856	$ 1,249	$ 1,223
Weighted average amortization period	19 years 7 months 6 days

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Future Intangible Asset Amortization Expense (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense, 2021	$ 71,705
Amortization expense, 2022	61,305
Amortization expense, 2023	52,328
Amortization expense, 2024	48,200
Amortization expense, 2025	44,872
Amortization expense, Thereafter	265,066
Net Intangible	$ 543,476	$ 25,288

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Assets and Liabilities Carried at Fair Value (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value on a recurring basis	$ 36	$ 1,277
Contingent consideration for acquisitions	60	203
Total liabilities at fair value on a recurring basis	2,288	546
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets at fair value on a recurring basis	36	1,277
Total liabilities at fair value on a recurring basis	2,228	343
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Contingent consideration for acquisitions	60	203
Total liabilities at fair value on a recurring basis	60	203
Diesel Fuel Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	36	189
Derivative liability	2,228	283
Diesel Fuel Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	36	189
Derivative liability	$ 2,228	283
Foreign Exchange Forward Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		60
Foreign Exchange Forward Contracts [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		60
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		1,088
Interest Rate Swaps [Member] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets		$ 1,088

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets and liabilities, additional transfers	$ 0	$ 0
Prudential Senior Notes [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes		100,000,000
Senior notes, fair value		$ 98,900,000
Senior Notes Payable [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Senior notes	350,000,000
Senior notes, fair value	$ 315,000,000
Contingent Consideration for Acquisitions [Member] | Discounted Cash Flow Valuation Technique [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted average cost of capital	9.50%	9.50%

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Changes in Fair Value of Recurring Fair Value Measurements Using Unobservable Inputs (Detail) - Contingent Consideration [Member] - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance beginning	$ 203	$ 578
Asset acquisition		40
Change in fair value		(6)
Payments of contingent consideration liability	(143)	(409)
Balance ending	$ 60	$ 203

Investment in Consolidated Affi

Investment in Consolidated Affiliates - Additional Information (Detail) - Subsidiaries [Member]	12 Months Ended
	Mar. 31, 2020JointVenture
Investments in and Advances to Affiliates [Line Items]
Number of unconsolidated joint venture participated	1
ADS Mexicana [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Investments in and Advances to Affiliates [Line Items]
Company's ownership percentage	51.00%
ADS Worldwide, Inc [Member]
Investments in and Advances to Affiliates [Line Items]
Company's ownership percentage	51.00%

Investment in Consolidated Af_2

Investment in Consolidated Affiliates - Assets and Liabilities of Joint Ventures (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Assets
Current assets	$ 666,211	$ 466,513
Property, plant and equipment, net	481,380	398,891
Other noncurrent assets	69,140	36,940
Total assets	2,369,888	1,042,159
Liabilities
Current liabilities	238,213	206,285
Total liabilities	1,585,306	541,524
ADS Mexicana [Member]
Assets
Current assets	18,357	18,683
Property, plant and equipment, net	12,438	17,054
Other noncurrent assets	1,317	1,396
Total assets	32,112	37,133
Liabilities
Current liabilities	6,350	6,581
Noncurrent liabilities	1,131	1,264
Total liabilities	$ 7,481	$ 7,845

Investment in Unconsolidated Af

Investment in Unconsolidated Affiliates - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Apr. 30, 2018	Dec. 31, 2017	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
South American Joint Venture [Member]
Investments in and Advances to Affiliates [Line Items]
Percentage of ownership in joint venture partner						50.00%
South American Joint Venture [Member]
Investments in and Advances to Affiliates [Line Items]
Percentage of ownership in joint ventures			50.00%
Receivables contributed		$ 5.8
Allowance for doubtful accounts		3	$ 3
Fair value of additional investment in joint venture		4.7
Gain on book value of receivables		$ 1.9
Difference between cost of investment and amount of underlying equity in net assets			$ 3.7	$ 4
Estimated remaining useful life of underlying property, plant and equipment			7 years
Amortization recognized			$ 0.3	$ 0.4	$ 0.5
Tigre-ADS USA [Member]
Investments in and Advances to Affiliates [Line Items]
Percentage of ownership in joint ventures			49.00%
Other assets, impairment charges	$ 0.3

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Detail) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
South American Joint Venture [Member]
Related Party Transaction [Line Items]
Maximum borrowings permitted under credit facility	$ 22,000,000
Debt, expiration date	Dec. 31, 2020
Percentage of debt guarantee	50.00%
Maximum potential payment under guarantee	$ 11,000,000
Outstanding principal balance including letters of credit	9,300,000	$ 12,300,000
Sales with related parties	700,000	1,300,000	$ 2,100,000
Sale with joint ventures	900,000	1,200,000	400,000
South American Joint Venture [Member] | US Dollar Denominated Loans [Member]
Related Party Transaction [Line Items]
Outstanding principal balance including letters of credit	$ 0
South American Joint Venture [Member] | Chilean Peso Denominated Loans [Member]
Related Party Transaction [Line Items]
Weighted average interest rate	5.32%
Tigre-ADS USA [Member]
Related Party Transaction [Line Items]
Purchases from related party	$ 2,000,000	$ 300,000	$ 2,000,000
Tigre-ADS USA [Member]
Related Party Transaction [Line Items]
Company's ownership percentage	49.00%	49.00%	49.00%
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member]
Related Party Transaction [Line Items]
Maximum borrowings permitted under credit facility	$ 12,000,000
Revolving credit facility maturity date	Jun. 22, 2018
Debt, expiration date	Jun. 22, 2022
Outstanding principal balance including letters of credit	$ 0	$ 0
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | ADS Mexicana [Member]
Related Party Transaction [Line Items]
Percentage of ownership in joint venture	49.00%

Debt - Long-Term Debt (Detail)

Debt - Long-Term Debt (Detail) - USD ($)	Mar. 31, 2020	Mar. 31, 2019
Debt Instrument [Line Items]
Total	$ 1,099,742,000	$ 236,827,000
Unamortized debt issuance costs	(2,419,000)	(2,293,000)
Current maturities	(7,955,000)	(25,932,000)
Long-term debt obligations	1,089,368,000	208,602,000
Term Loan Facility [Member]
Debt Instrument [Line Items]
Revolving Credit Facility	648,250,000
Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes	350,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving Credit Facility	100,000,000
PNC Credit Agreement [Member]
Debt Instrument [Line Items]
Revolving Credit Facility		134,400,000
Equipment Financing [Member]
Debt Instrument [Line Items]
Revolving Credit Facility	$ 1,492,000	2,427,000
Prudential Senior Notes [Member]
Debt Instrument [Line Items]
Senior notes		$ 100,000,000

Debt (Bridge Credit Facility) -

Debt (Bridge Credit Facility) - Additional Information (Detail) - USD ($)	Sep. 24, 2019	Sep. 23, 2019	Sep. 10, 2019	Jul. 31, 2019	Sep. 30, 2019	Mar. 31, 2020	Mar. 31, 2018
Debt Instrument [Line Items]
Repayment of borrowings						$ 177,900,000
Repayment of notes						1,300,000,000	$ 72,500,000
Proceeds from Senior Notes						350,000,000	$ 75,000,000
Principal payment from common stock offering			$ 300,000,000			$ 293,648,000
5.0% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Aggregate principal amount		$ 350,000,000
Deferred financing fees capitalized		2,100,000
Bridge Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility				$ 350,000,000
Amount borrowed				145,000,000
Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility	$ 50,000,000			50,000,000
Sublimit of Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility	50,000,000			50,000,000
Bridge Credit Facility [Member]
Debt Instrument [Line Items]
Repayment of borrowings			$ 300,000,000
Deferred financing fees capitalized				46,900,000
Decrease in deferred financing costs due to refunds received				14,900,000
Senior Secured Credit Facility
Debt Instrument [Line Items]
Proceeds from Senior Notes	700,000,000
Deferred financing fees capitalized	$ 400,000
Bridge Loan Facility [Member]
Debt Instrument [Line Items]
Aggregate principal amount				1,300,000,000
Amount borrowed				$ 1,300,000,000
Repayment of notes		300,000,000
Bridge Loan Facility [Member] | 5.0% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Repayment of notes		300,000,000
Proceeds from Senior Notes		$ 300,000,000			$ 350,000,000

Debt (Repayment of Prudential S

Debt (Repayment of Prudential Senior Notes) - Additional Information (Detail) - Prudential Senior Notes [Member] $ in Millions	Jul. 29, 2019USD ($)
Debt Instrument [Line Items]
Repayments of debt	$ 104.4
Write-off of unamortized deferred financing fees and prepayment premium or penalty	$ 4.2

Debt (Repayment of PNC Credit A

Debt (Repayment of PNC Credit Agreement) - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Debt Instrument [Line Items]
Write-off of unamortized deferred financing fees		$ 34,476	$ 735	$ 934
PNC Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of debt	$ 239,200
Write-off of unamortized deferred financing fees	$ 2,000

Debt (Issuance of Senior Notes

Debt (Issuance of Senior Notes due 2027) - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 23, 2019	Mar. 31, 2020	Mar. 31, 2018	Jul. 31, 2019
Debt Instrument [Line Items]
Repayment of notes		$ 1,300,000	$ 72,500
Bridge Loan Facility [Member]
Debt Instrument [Line Items]
Aggregate principal amount				$ 1,300,000
Repayment of notes	$ 300,000
5.0% Senior Notes due 2027 [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 350,000
Debt instrument, interest rate	5.00%
Debt instrument, description of payment terms		Interest on the Senior Notes will be payable semi-annually in cash in arrears on March 31 and September 30 of each year, commencing on March 31, 2020, at a rate of 5.0% per annum.
Debt instrument, frequency of periodic payment		semi-annually
Debt instrument, date of first required payment	Mar. 31, 2020
Debt instrument, maturity date	Sep. 30, 2027
Deferred financing costs	$ 2,100
5.0% Senior Notes due 2027 [Member] | Prior to September 30, 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage of principal amount redeemed		105.00%
Debt instrument, redemption price, percentage of principal amount redeemed excluding "make-whole" premium		100.00%
5.0% Senior Notes due 2027 [Member] | Maximum [Member] | Prior to September 30, 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, redemption price, percentage		40.00%
5.0% Senior Notes due 2027 [Member] | Bridge Loan Facility [Member]
Debt Instrument [Line Items]
Repayment of notes	$ 300,000

Debt (New Senior Secured Credit

Debt (New Senior Secured Credit Facility) - Additional Information (Detail) - USD ($)	Sep. 24, 2019	Sep. 10, 2019	Mar. 31, 2020	Jul. 31, 2019
Debt Instrument [Line Items]
Repayment of borrowings			$ 177,900,000
Term Loan Facility [Member]
Debt Instrument [Line Items]
Aggregate principal amount	$ 700,000,000
Repayment of borrowings			51,800,000
Debt instrument term	7 years
Bridge Credit Facility [Member]
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 700,000,000
Repayment of borrowings		$ 300,000,000
Deferred financing fees capitalized				$ 46,900,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility	$ 350,000,000
Outstanding letters of credit			$ 8,500,000
Debt instrument term	5 years
Commitment fee on undrawn portion, percentage			0.20%
Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility	$ 50,000,000			50,000,000
Sublimit of Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowings permitted under credit facility	50,000,000			$ 50,000,000
Senior Secured Credit Facility
Debt Instrument [Line Items]
Deferred financing fees capitalized	$ 400,000

Debt - Maturities of Long-term

Debt - Maturities of Long-term Debt (Excluding Interest and Deferred Financing Costs) (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Debt Disclosure [Abstract]
2021	$ 7,955
2022	7,532
2023	7,000
2024	7,000
2025	107,000
Thereafter	963,255
Total	$ 1,099,742	$ 236,827

Derivative Transactions - Summa

Derivative Transactions - Summary of Fair Values for Various Derivatives (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Receivables [Member] | Diesel Fuel Option Collars and Swaps [Member]
Derivatives, Fair Value [Line Items]
Asset	$ 21	$ 127
Receivables [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Asset		566
Other Assets [Member] | Diesel Fuel Option Collars and Swaps [Member]
Derivatives, Fair Value [Line Items]
Asset	15	62
Other Assets [Member] | Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Asset		522
Other Accrued Liabilities [Member] | Diesel Fuel Option Collars and Swaps [Member]
Derivatives, Fair Value [Line Items]
(Liability)	(2,000)	(201)
Other Accrued Liabilities [Member] | Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
(Liability)		(60)
Other Liabilities [Member] | Diesel Fuel Option Collars and Swaps [Member]
Derivatives, Fair Value [Line Items]
(Liability)	$ (228)	$ (82)

Derivative Transactions - Sched

Derivative Transactions - Schedule of Cash Settlements and Net Losses and Net (Gains) on Mark-to-Market Adjustments for Changes in Fair Value of Derivative Contracts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Derivatives, Fair Value [Line Items]
Total net unrealized mark to market losses (gains)	$ 3,128	$ 2,346	$ (3,244)
Total net realized losses (gains)	837	(1,190)	(476)
Interest Rate Swaps [Member]
Derivatives, Fair Value [Line Items]
Total net unrealized mark to market losses (gains)	1,029	1,712	(2,801)
Total net realized losses (gains)	378	(329)
Foreign Exchange Forward Contracts [Member]
Derivatives, Fair Value [Line Items]
Total net unrealized mark to market losses (gains)		60
Total net realized losses (gains)	102	(163)
Diesel Fuel Option Collars [Member]
Derivatives, Fair Value [Line Items]
Total net unrealized mark to market losses (gains)	2,099	574	(443)
Total net realized losses (gains)	$ 357	$ (698)	$ (476)

Commitments and Contingencies (

Commitments and Contingencies (Purchase Commitments) - Additional Information (Detail) - Inventory [Member] $ in Millions	12 Months Ended
	Mar. 31, 2020USD ($)
Purchase Commitment, Excluding Long-term Commitment [Line Items]
Purchase contracts period range, start	1 month
Purchase contracts period range, end	12 months
Total purchase commitment	$ 0

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Average fair value of shares allocated under ESOP, per share		$ 21.31	$ 19.95	$ 18.40
Compensation expense related to allocation of ESOP shares		$ 20,100,000	$ 15,300,000	$ 11,700,000
Trustee retained for dividends on unallocated ADS shares		$ 0	3,300,000	3,200,000
Cash dividend declared		$ 0.09
Defined contribution postretirement benefit plan, costs recognized		$ 500,000	400,000	700,000
Covid-19 Pandemic pay, description		to all hourly employees that each would be entitled to the equivalent of two weeks, or 80 hours, of pandemic pay regardless of whether they experienced any interruption of employment.
Pandemic pay costs in other accrued liabilities		$ 4,800,000
Profit-Sharing Plan [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Contribution to the profit sharing plan		0	0	0
Other Liabilities [Member] | Executive Retirement Expense [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Executive termination payment obligation		2,600,000	4,300,000
General and Administrative Expenses [Member] | Executive Retirement Expense [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Compensation expense (benefit)		$ 200,000	$ (200,000)	$ 1,500,000
Special Dividend [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Dividend to be paid		Jun. 14, 2019
Dividend record date		Jun. 3, 2019
Cash dividend declared		$ 1
Redeemable Convertible Preferred Stock [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Fair value of shares allocated under ESOP, per share		22.70	$ 19.90	$ 20
Preferred stock, redemption value per share		$ 0.7818
Preferred stock, unpaid cumulative dividends		$ 0
Preferred stock, dividend rate percentage	2.50%	2.50%
Redeemable convertible preferred stock liquidation		$ 0.7818
Convertible preferred stock, converted to common stock		0.7692
Dividend to be paid	Mar. 31, 2020
Dividend record date	Mar. 15, 2020
Cash dividend declared		$ 0.0195	$ 0.0195
Employee stock ownership plan number of shares approved by the board of directors to the plan		1,000,000	800,000
Employee stock ownership plan allocated as shares		18,756,000	7,392,000
Redeemable Convertible Preferred Stock [Member] | Dividend Declared [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Employee stock ownership plan allocated as shares		400,000	100,000
Employee Stock Ownership Plan (ESOP) [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Number of days, share of redeemable convertible preferred stock converted into common stock following repayment of the ESOP Loan		30 days
Employee stock ownership plan participation description		Employees of ADS who have reached the age of 18 are generally eligible to participate in the Plan on March 31 after six months of service.
Employee stock ownership plan stock ownership description		Upon attainment of age 50 and seven years of participation in the Plan, a participant may elect to diversify specified percentages of the number of shares of ADS stock credited to the participant’s ESOP stock account in compliance with applicable law.
Employee Stock Ownership Plan (ESOP) [Member] | ADS [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Debt instrument, term		30 years

Employee Benefit Plans - Summar

Employee Benefit Plans - Summarized Cash and Stock Dividends on Allocated Redeemable Convertible Preferred Stock (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Annual stock dividend	$ 359	$ 134	$ 134
Total ESOP required dividends	$ 168,610
Required dividend per share	$ 0.09
Redeemable Convertible Preferred Stock [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Total cash dividends	$ 10,847	1,913
Total ESOP required dividends	$ 366	$ 144
Allocated shares	18,756	7,392
Required dividend per share	$ 0.0195	$ 0.0195
Redeemable Convertible Preferred Stock [Member] | Quarterly Cash Dividends [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Total cash dividends	$ 10,840	$ 1,903
Redeemable Convertible Preferred Stock [Member] | Annual Cash Dividend [Member]
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Total cash dividends	7	10
Annual cash dividend	7	10
Redeemable Convertible Preferred Stock [Member] | Annual Stock Dividend
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Annual stock dividend	$ 359	$ 134

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock-based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 12,269	$ 6,532	$ 7,121
Non-Employee Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	1,226	1,049	1,232
Equity-Classified Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	2,554	2,550	4,148
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	3,807	2,064	1,741
Performance-based Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	4,682	869
Cost of Goods Sold [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	897	317	179
Selling Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	426	180	105
General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 10,946	$ 6,035	$ 6,837

Stock-Based Compensation - Su_2

Stock-Based Compensation - Summary of Assumption Used in Estimate Fair Value of Stock Options (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected stock price volatility, minimum	30.10%	30.30%	32.10%
Expected stock price volatility, maximum	30.90%	31.10%	35.60%
Risk-free interest rate, minimum	1.40%	2.90%	1.90%
Risk-free interest rate, maximum	2.30%	3.10%	2.20%
Weighted-average expected option life (years)	6 years	6 years
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock price	$ 27.44	$ 25.75	$ 19.35
Weighted-average expected option life (years)			5 years 7 months 6 days
Dividend yield	0.90%	1.10%	1.10%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock price	$ 41.85	$ 27.99	$ 22.95
Weighted-average expected option life (years)			6 years
Dividend yield	1.30%	1.20%	1.50%

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock Options) - Additional Information (Detail) $ in Millions	12 Months Ended
	Mar. 31, 2020USD ($)Installmentshares	Mar. 31, 2019USD ($)shares	Mar. 31, 2018USD ($)shares
2000 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair value of options vested | shares	100,000	0	0
Weighted average fair value of options granted | shares	0	0	0
Aggregate intrinsic value of options outstanding	$ 1
Aggregate intrinsic value of options exercisable	0.6
Intrinsic value of options exercised	0.2	$ 0.8	$ 0.5
2000 Stock Option Plan [Member] | Liability-Classified Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based awards, unrecognized compensation expense	$ 0.1
Unrecognized compensation cost, weighted average service period for recognition	1 year 3 months 18 days
2000 Stock Option Plan [Member] | Liability-Classified Stock Options [Member] | Management [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards, expiration period	10 years
Stock awards, number of annual installments for vesting | Installment	3
Stock based awards, shares available for grant | shares	0
2013 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock based awards, shares available for grant | shares	0
Stock-based awards, unrecognized compensation expense	$ 0.1
Unrecognized compensation cost, weighted average service period for recognition	10 months 24 days
Weighted average fair value of options granted | shares	0
2013 Stock Option Plan [Member] | Management [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards, expiration period	10 years
2013 Stock Option Plan [Member] | Management [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards, number of annual installments for vesting | Installment	3
2013 Stock Option Plan [Member] | Management [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards, number of annual installments for vesting | Installment	5
2013 Stock Option Plan [Member] | Liability-Classified Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value of options outstanding	$ 5.6
Aggregate intrinsic value of options exercisable	5.5
Intrinsic value of options exercised	13.2
Intrinsic value of options vested	$ 0.8	$ 2.6	$ 4.7

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Option Activity (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
2000 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	82,000
Number of Shares, Granted	0	0	0
Number of Shares, Exercised	(8,000)
Number of Shares, Forfeited	(3,000)
Number of Shares, Outstanding, Ending Balance	71,000	82,000
Number of Shares, Vested at end of year	37,000
Number of Shares, Unvested at end of year	34,000	54,000
Number of Shares, Vested and expected to vest at end of year	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 14.64
Weighted Average Exercise Price, Granted	0
Weighted Average Exercise Price, Exercised	13.87
Weighted Average Exercise Price, Forfeited	15.74
Weighted Average Exercise Price, Outstanding, Ending Balance	14.69	$ 14.64
Weighted Average Exercise Price, Vested at end of period	13.73
Weighted Average Exercise Price, Unvested at end of year	15.74
Weighted Average Exercise Price, Fair value of options granted during the year	$ 0
Weighted Average Remaining Contractual Term (in years), Outstanding	3 years 4 months 24 days	4 years 3 months 18 days
Weighted Average Remaining Contractual Term (in years), Vested at end of year	2 years 9 months 18 days
Weighted Average Remaining Contractual Term (in years), Unvested at end of year	4 years
2013 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	1,120,000
Number of Shares, Granted	0
Number of Shares, Exercised	(555,000)
Number of Shares, Outstanding, Ending Balance	565,000	1,120,000
Number of Shares, Vested at end of year	542,000
Number of Shares, Unvested at end of year	23,000	121,000
Number of Shares, Vested and expected to vest at end of year	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 16.81
Weighted Average Exercise Price, Granted	0
Weighted Average Exercise Price, Exercised	14.11
Weighted Average Exercise Price, Outstanding, Ending Balance	19.45	$ 16.81
Weighted Average Exercise Price, Vested at end of period	19.25
Weighted Average Exercise Price, Unvested at end of year	24.12
Weighted Average Exercise Price, Fair value of options granted during the year	$ 0
Weighted Average Remaining Contractual Term (in years), Outstanding	4 years 8 months 12 days	4 years 10 months 24 days
Weighted Average Remaining Contractual Term (in years), Vested at end of year	4 years 7 months 6 days
Weighted Average Remaining Contractual Term (in years), Unvested at end of year	6 years
2017 Omnibus Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Outstanding, Beginning Balance	457,000
Number of Shares, Granted	336,000
Number of Shares, Exercised	(8,000)
Number of Shares, Outstanding, Ending Balance	785,000	457,000
Number of Shares, Vested at end of year	212,000
Number of Shares, Unvested at end of year	573,000	388,000
Number of Shares, Vested and expected to vest at end of year	0
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 23.19
Weighted Average Exercise Price, Granted	27.51
Weighted Average Exercise Price, Exercised	25.75
Weighted Average Exercise Price, Outstanding, Ending Balance	25.01	$ 23.19
Weighted Average Exercise Price, Vested at end of period	22.04
Weighted Average Exercise Price, Unvested at end of year	26.11
Weighted Average Exercise Price, Fair value of options granted during the year	$ 8.02
Weighted Average Remaining Contractual Term (in years), Outstanding	8 years 4 months 24 days	8 years 10 months 24 days
Weighted Average Remaining Contractual Term (in years), Vested at end of year	7 years 8 months 12 days
Weighted Average Remaining Contractual Term (in years), Unvested at end of year	8 years 8 months 12 days

Stock-Based Compensation - Su_3

Stock-Based Compensation - Summary of Unvested Stock Option Grants (Detail) - $ / shares	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
2000 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year	54,000
Number of Shares, Granted	0	0	0
Number of Shares, Vested	(17,000)
Number of Shares, Forfeitures	(3,000)
Number of Shares, Unvested at end of year	34,000	54,000
Weighted Average Grant Date Fair Value, Unvested at beginning of year	$ 6.76
Weighted Average Grant Date Fair Value, Granted	0
Weighted Average Grant Date Fair Value, Vested	8.72
Weighted Average Grant Date Fair Value, Forfeitures	8.72
Weighted Average Grant Date Fair Value, Unvested at end of year	$ 8.72	$ 6.76
2013 Stock Option Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year	121,000
Number of Shares, Granted	0
Number of Shares, Vested	(98,000)
Number of Shares, Forfeitures	0
Number of Shares, Unvested at end of year	23,000	121,000
Weighted Average Grant Date Fair Value, Unvested at beginning of year	$ 7.68
Weighted Average Grant Date Fair Value, Granted	0
Weighted Average Grant Date Fair Value, Vested	7.80
Weighted Average Grant Date Fair Value, Forfeitures	0
Weighted Average Grant Date Fair Value, Unvested at end of year	$ 7.20	$ 7.68
2017 Omnibus Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year	388,000
Number of Shares, Granted	336,000
Number of Shares, Vested	(151,000)
Number of Shares, Unvested at end of year	573,000	388,000
Weighted Average Grant Date Fair Value, Unvested at beginning of year	$ 7.19
Weighted Average Grant Date Fair Value, Granted	8.02
Weighted Average Grant Date Fair Value, Vested	7.01
Weighted Average Grant Date Fair Value, Unvested at end of year	$ 7.73	$ 7.19

Stock-Based Compensation (2008

Stock-Based Compensation (2008 Restricted Stock Plan) - Additional Information (Detail) - 2008 Restricted Stock Plan [Member] - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based awards, vesting period	5 years
Stock based awards, shares available for grant	0
Unrecognized compensation expense	$ 0.1
Unrecognized compensation cost, weighted average service period for recognition	1 year
Intrinsic value of options vested	$ 0.9	$ 1.4	$ 2.9

Stock-Based Compensation - Su_4

Stock-Based Compensation - Summary of Unvested Restricted Stock Grants (Detail) shares in Thousands	12 Months Ended
	Mar. 31, 2020$ / sharesshares
2008 Restricted Stock Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year | shares	44
Number of shares, Granted | shares	0
Number of Shares, Vested | shares	(37)
Number of Shares, Forfeited | shares	(1)
Number of Shares, Unvested at end of year | shares	6
Weighted Average Grant Date Fair Value, Unvested at beginning of year | $ / shares	$ 24.17
Weighted Average Grant Date Fair Value, Granted | $ / shares	0
Weighted Average Grant Date Fair Value, Vested | $ / shares	24.18
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	24.20
Weighted Average Grant Date Fair Value, Unvested at end of year | $ / shares	$ 24.10
2017 Omnibus Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year | shares	172
Number of shares, Granted | shares	308
Number of Shares, Vested | shares	(90)
Number of Shares, Forfeited | shares	(2)
Number of Shares, Unvested at end of year | shares	388
Weighted Average Grant Date Fair Value, Unvested at beginning of year | $ / shares	$ 25.02
Weighted Average Grant Date Fair Value, Granted | $ / shares	31.96
Weighted Average Grant Date Fair Value, Vested | $ / shares	25.63
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	27.13
Weighted Average Grant Date Fair Value, Unvested at end of year | $ / shares	$ 30.38

Stock-Based Compensation (2017

Stock-Based Compensation (2017 Omnibus Plan) - Additional Information (Detail) - 2017 Omnibus Plan [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	May 24, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for awards	1,800,000
Stock-based awards, unrecognized compensation expense	$ 2.9
Unrecognized compensation cost, weighted average service period for recognition	1 year 9 months 18 days
Aggregate intrinsic value of options outstanding	$ 3.5
Aggregate intrinsic value of options exercisable	1.6
Intrinsic value of options exercised	$ 0.1
Number of Shares, Vested	151,000
Share-based compensation award description	the performance units, 50% of the award is based upon the achievement of certain levels of Return on Invested Capital for the performance period and 50% is based upon the achievement of certain levels of Free cash flow for the performance period
Performance awards performance period	3 years
Number of shares, Granted	308,000
Weighted average fair value of options granted	$ 8.02
IWT [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation award description	the performance units based on the Infiltrator Water Technologies reportable segment, 75% of the award is based upon the achievement of certain levels of Infiltrator Water Technologies Adjusted EBITDA for the performance period and 25% is based upon the achievement of certain levels of Infiltrator Water Technologies Free cash flow for the performance period
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost, weighted average service period for recognition	2 years 1 month 6 days
Unrecognized compensation expense	$ 8.2
Intrinsic value of options vested	$ 2.3	$ 2
Number of Shares, Vested			0
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unrecognized compensation cost, weighted average service period for recognition	1 year 10 months 24 days
Unrecognized compensation expense	$ 9.6
Intrinsic value of options vested	$ 0	$ 0.1	$ 0
Number of shares, Granted	274,000
Weighted average fair value of options granted	$ 33.27	$ 25.84
Performance Shares [Member] | IWT [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance awards performance period	3 years
Number of shares, Granted	100,000
Number of performance units granted, Value	$ 2.7
Predetermined Synergies Performance Shares [Member] | IWT [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance awards performance period	3 years
Number of shares, Granted	100,000
Number of performance units granted, Value	$ 2.9
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock approved for issuance				3,500,000

Stock-Based Compensation - Su_5

Stock-Based Compensation - Summary of Performance Units Granted (Detail) - 2017 Omnibus Plan [Member] shares in Thousands	12 Months Ended
	Mar. 31, 2020$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year | shares	172
Number of shares, Granted | shares	308
Number of Shares, Vested | shares	(90)
Number of Shares, Forfeited | shares	(2)
Number of Shares, Unvested at end of year | shares	388
Weighted Average Grant Date Fair Value, Unvested at beginning of year | $ / shares	$ 25.02
Weighted Average Grant Date Fair Value, Granted | $ / shares	31.96
Weighted Average Grant Date Fair Value, Vested | $ / shares	25.63
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	27.13
Weighted Average Grant Date Fair Value, Unvested at end of year | $ / shares	$ 30.38
Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Unvested at beginning of year | shares	115
Number of shares, Granted | shares	274
Number of Shares, Unvested at end of year | shares	389
Weighted Average Grant Date Fair Value, Unvested at beginning of year | $ / shares	$ 25.85
Weighted Average Grant Date Fair Value, Granted | $ / shares	33.27
Weighted Average Grant Date Fair Value, Unvested at end of year | $ / shares	$ 31.07

Income Taxes - Components of In

Income Taxes - Components of Income before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
United States	$ (186,209)	$ 103,559	$ 72,109
Foreign	6,595	8,051	4,833
(Loss) income before income taxes	$ (179,614)	$ 111,610	$ 76,942

Income Taxes - Components of _2

Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Current:
Federal	$ 10,867	$ 11,575	$ 17,107
State and local	4,655	3,998	3,541
Foreign	1,546	2,050	2,242
Total current tax expense	17,068	17,623	22,890
Deferred:
Federal	210	11,745	(11,236)
State and local	(1,228)	1,795	(55)
Foreign	(1,958)	(1,114)	(188)
Total deferred tax expense (benefit)	(2,976)	12,426	(11,479)
Total Income tax expense	$ 14,092	$ 30,049	$ 11,411

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Effective Tax Rate and Statutory Federal Income Tax Rate (Detail)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Federal statutory rate	21.00%	21.00%	31.50%
ESOP stock appreciation, ESOP dividends and special dividend	(30.30%)	3.20%	5.40%
Effect of tax rate of foreign subsidiaries	0.60%	(0.30%)	0.70%
State and local taxes—net of federal income tax benefit	(1.70%)	4.60%	3.60%
Uncertain tax position change	1.20%	(1.30%)	0.30%
Impact of tax reform			(19.40%)
Equity-based compensation	1.10%	(0.40%)	0.50%
Return to provision - federal and state	0.30%	(0.20%)	(5.00%)
Qualified production activity deduction			(2.50%)
Executive compensation	(0.80%)	1.10%	0.10%
Net operating losses	1.90%
Credits and incentives	0.70%	(1.00%)	(0.50%)
Other	(1.90%)	0.20%	0.10%
Effective rate	(7.90%)	26.90%	14.80%

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Effective Tax Rate and Statutory Federal Income Tax Rate (Parenthetical) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Taxes [Line Items]
Total stock-based compensation expense	$ 12,269	$ 6,532	$ 7,121
Employee Stock Ownership Plan (ESOP) [Member]
Income Taxes [Line Items]
Non-deductible stock appreciation and deductible dividends	$ 242,900
Decrease in effective tax rate	28.40%
Employee Stock Ownership Plan (ESOP) [Member] | Special Dividend [Member]
Income Taxes [Line Items]
Total stock-based compensation expense	$ 246,800

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	Jul. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Taxes [Line Items]
Operating loss carryforwards, expiration term		5 years
Income tax benefit related to federal net operation loss		$ (14,092)	$ (30,049)	$ (11,411)
Undistributed earnings on foreign subsidiaries		26,500
Unrecognized tax benefit that would decrease income tax expense		3,343	5,681	$ 7,593	$ 6,196
Decrease in unrecognized tax benefit related to income tax expense		3,300
Accrued interest and penalties related to unrecognized tax benefits		800	$ 1,500
Other Accrued Liabilities [Member]
Income Taxes [Line Items]
Short-term portion of unrecognized tax benefit		1,500
Maximum [Member]
Income Taxes [Line Items]
Increase in unrecognized tax benefits is reasonably possible		1,500
IWT [Member]
Income Taxes [Line Items]
Total purchase price	$ 132,400	132,400
Purchase price related to step up of GAAP basis for fair market valuations	82,300
Deferred tax liabilities acquired	50,100
Business combination, acquired federal net operating loss	24,000
Income tax benefit related to federal net operation loss		3,400
IWT [Member] | State Credit Carryforward [Member]
Income Taxes [Line Items]
Income tax benefit related to federal net operation loss		800
Valuation allowance		500
IWT [Member] | State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Deferred tax assets related to state NOLs		900
Valuation allowance		$ 100
IWT [Member] | State and Local Jurisdiction [Member] | Minimum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration term		5 years
IWT [Member] | State and Local Jurisdiction [Member] | Maximum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration term		20 years
IWT [Member] | Foreign [Member]
Income Taxes [Line Items]
Valuation allowance		$ 100
Deferred tax assets related to foreign NOLs		$ 300
IWT [Member] | Foreign [Member] | Minimum [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration term		20 years
IWT [Member] | Intangible Assets [Member]
Income Taxes [Line Items]
Purchase price related to step up of GAAP basis for fair market valuations	$ 80,200

Income Taxes - Deferred Tax Ass

Income Taxes - Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Deferred tax assets:
Receivable and other allowances	$ 1,122	$ 1,546
Inventory	2,065	3,217
Stock-based compensation	2,770	3,186
Worker’s compensation	2,317	2,063
Net operating loss and credit carryforwards	2,059	152
Operating lease liabilities	6,160
Other	5,562	4,673
Total deferred tax assets	22,055	14,837
Less: valuation allowance	(941)	(269)
Total net deferred tax assets	21,114	14,568
Deferred tax liabilities:
Intangible assets	121,276	2,512
Property, plant and equipment	63,649	52,218
Operating lease assets	6,147
Goodwill	4,527	4,078
Other	600	1,385
Total deferred tax liabilities	196,199	60,193
Net deferred tax liability	$ 175,085	$ 45,625

Income Taxes - Net Deferred Tax

Income Taxes - Net Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2020	Mar. 31, 2019
Net non-current deferred tax liabilities	$ 175,616	$ 45,963
Other Assets [Member]
Net non-current deferred tax assets	$ 531	$ 338

Income Taxes - Unrecognized Tax

Income Taxes - Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 5,681	$ 7,593	$ 6,196
Tax positions taken in current year		164	81
Decreases in tax positions for prior years	(1,398)	(198)
Increases in tax positions for prior years	1,907	136	5,108
Settlements	(124)	(200)
Lapse of statute of limitations	(2,589)	(1,595)	(3,940)
Decrease in foreign translation adjustment	(134)	(219)
Increase in foreign translation adjustment			148
Balance at end of year	$ 3,343	$ 5,681	$ 7,593

Net Income Per Share and Stoc_3

Net Income Per Share and Stockholders' Equity - Summary of Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
NET INCOME PER SHARE — BASIC:
Net (loss) income attributable to ADS	$ 2,305	$ 23,288	$ 7,589	$ (226,356)	$ 1,010	$ 15,812	$ 28,670	$ 32,280	$ (193,174)	$ 77,772	$ 62,007	$ 62,007
Dividends paid to redeemable convertible preferred stockholders									(11,206)	(2,047)		(1,858)
Dividends paid to unvested restricted stockholders									(338)	(69)		(49)
Net income available to common stockholders and participating securities									(204,718)	75,656		60,100
Undistributed income allocated to participating securities										(5,474)		(4,514)
Net income available to common stockholders — Basic									$ (204,718)	$ 70,182		$ 55,586
Weighted average number of common shares outstanding — Basic									63,820	57,025	55,696	55,696
Net (loss) income per common share — Basic	$ 0.01	$ 0.28	$ 0.10	$ (4.06)	$ 0.01	$ 0.25	$ 0.45	$ 0.51	$ (3.21)	$ 1.23	$ 1	$ 1
NET INCOME PER SHARE — DILUTED:
Net income available to common stockholders — Diluted									$ (204,718)	$ 70,182		$ 55,586
Weighted average number of common shares outstanding — Basic									63,820	57,025	55,696	55,696
Weighted average number of common shares outstanding — Diluted									63,820	57,611	56,334	56,334
Net (loss) income per common share — Diluted	$ 0.01	$ 0.28	$ 0.10	$ (4.06)	$ 0.01	$ 0.25	$ 0.45	$ 0.51	$ (3.21)	$ 1.22	$ 0.99	$ 0.99
Potentially dilutive securities excluded as anti- dilutive									14,449	5,966		6,167
Restricted Stock - Nonparticipating [Member]
NET INCOME PER SHARE — DILUTED:
Dilutive securities										39
Exercise of Stock Options [Member]
NET INCOME PER SHARE — DILUTED:
Dilutive securities										547		638

Net Income Per Share and Stoc_4

Net Income Per Share and Stockholders' Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	Sep. 10, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Feb. 28, 2017
Equity Class Of Treasury Stock [Line Items]
Common stock, par value		$ 0.01	$ 0.01
Proceeds from issuance of common stock after deducting underwriting discounts and commissions and offering expenses	$ 300,000	$ 293,648
Stock repurchase program amount authorized					$ 50,000
Cash dividend declared		$ 0.09
Dividend payment		$ 81,600
Additional stock-based compensation expense		12,269	$ 6,532	$ 7,121
Cost of Goods Sold - ESOP special dividend compensation and Selling, General and Administrative Expenses [Member]
Equity Class Of Treasury Stock [Line Items]
Additional stock-based compensation expense		$ 246,800
ESOP [Member]
Equity Class Of Treasury Stock [Line Items]
Number of redeemable convertible preferred stock allocated to ESOP participants		11,600,000
Amount of dividend from unallocated redeemable convertible preferred stock held in the ESOP trust to repay ESOP loan		$ 12,000
Special Dividend [Member]
Equity Class Of Treasury Stock [Line Items]
Cash dividend declared		$ 1
Dividend payable date		Jun. 14, 2019
Dividend payable, date of record		Jun. 3, 2019
Special Dividend [Member] | ESOP [Member]
Equity Class Of Treasury Stock [Line Items]
Additional stock-based compensation expense		$ 246,800
Common Stock [Member]
Equity Class Of Treasury Stock [Line Items]
Aggregate shares of common stock issued and sold		10,350,000
Common stock repurchases, Shares		0	0
Stock repurchase program amount authorized		$ 42,100
Common Stock Offering [Member]
Equity Class Of Treasury Stock [Line Items]
Aggregate shares of common stock issued and sold	10,350,000
Common stock, par value	$ 0.01
Shares price per share	$ 29.75
Proceeds from issuance of common stock after deducting underwriting discounts and commissions and offering expenses	$ 293,600

Other Accrued Liabilities - Sch

Other Accrued Liabilities - Schedule of Other Accrued Liabilities (Detail) - USD ($) $ in Thousands		Mar. 31, 2020	Mar. 31, 2019
Payables And Accruals [Abstract]
Accrued compensation and benefits	[1]	$ 33,215	$ 18,108
Accrued rebate liability	[2]	14,479	12,313
Lease liability - Operating leases		7,757
Self-insurance accruals		12,486	11,697
Other		33,179	19,783
Total accrued liabilities		$ 101,116	$ 61,901
[1]	Accrued compensation and benefits is primarily comprised of accrued payroll, bonuses and commissions.
[2]	Accrued rebate liability represents the Company’s estimated rebates to be paid to customers.

Business Segment Information -

Business Segment Information - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2020Segment
Segment Reporting [Abstract]
Number of reportable segments	3

Business Segment Information _2

Business Segment Information - Schedule of Revenue from Reportable Segments by Product Type (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Net Sales	$ 370,768	$ 393,424	$ 495,905	$ 413,708	$ 272,218	$ 318,113	$ 406,555	$ 387,847	$ 1,673,805	$ 1,384,733	$ 1,330,354
Pipe Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									952,603	868,805	844,875
Infiltrator Water Technologies Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									169,348
International Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									148,581	160,602	155,922
International Segment [Member] | Pipe [Member]
Segment Reporting Information [Line Items]
Net Sales									108,624	122,836	119,207
International Segment [Member] | Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Net Sales									39,957	37,766	36,715
Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Net Sales									403,273	355,326	329,557
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net Sales									1,673,805	1,384,733	1,330,354
Operating Segments [Member] | Pipe Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									954,633	868,805	844,875
Operating Segments [Member] | Infiltrator Water Technologies Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									211,005
Operating Segments [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									148,581	160,602	155,922
Operating Segments [Member] | International Segment [Member] | Pipe [Member]
Segment Reporting Information [Line Items]
Net Sales									108,624	122,836	119,207
Operating Segments [Member] | International Segment [Member] | Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Net Sales									39,957	37,766	36,715
Operating Segments [Member] | Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Net Sales									403,273	$ 355,326	$ 329,557
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Net Sales									(43,687)
Intersegment Eliminations [Member] | Pipe Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									(2,030)
Intersegment Eliminations [Member] | Infiltrator Water Technologies Segment [Member]
Segment Reporting Information [Line Items]
Net Sales									$ (41,657)

Business Segment Information _3

Business Segment Information - Schedule of Financial Information Attributable to Reportable Segments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Segment adjusted gross profit	$ 574,086	$ 396,922	$ 373,221
Depreciation and amortization	124,940	71,900	75,003
Capital expenditures	67,677	43,412	41,709
Operating Segments [Member] | Pipe Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	239,531	191,002	186,330
Depreciation and amortization	46,611	49,419	51,236
Capital expenditures	33,629	34,878	32,393
Operating Segments [Member] | Infiltrator Water Technologies Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	98,245
Depreciation and amortization	7,159
Capital expenditures	24,917
Operating Segments [Member] | International Segment [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	36,999	37,191	31,725
Depreciation and amortization	6,013	5,938	6,431
Capital expenditures	2,623	3,765	2,147
Operating Segments [Member] | Allied Products and Other [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	201,206	168,729	155,166
Depreciation and amortization	65,157	16,543	17,336
Capital expenditures	6,508	$ 4,769	$ 7,169
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Segment adjusted gross profit	$ (1,895)

Business Segment Information _4

Business Segment Information - Reconciliation of Gross Profit to Segment Adjusted Gross Profit (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Gross profit	$ 108,755	$ 123,358	$ 146,524	$ (62,158)	$ 59,504	$ 72,399	$ 95,373	$ 99,691	$ 316,479	$ 326,967	$ 302,481
Depreciation and amortization									62,225	59,164	62,113
ESOP and stock-based compensation expense									14,319	10,791	8,627
ESOP special dividend compensation									168,610
COVID-19 Related Expenses									4,573
Inventory step up									7,880
Total Segment Adjusted Gross Profit									574,086	$ 396,922	$ 373,221
Infiltrator Water Technologies [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Inventory step up									$ 7,880

Business Segment Information _5

Business Segment Information - Net Sales and Long-Lived Asset by Geographic Location (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales	$ 370,768	$ 393,424	$ 495,905	$ 413,708	$ 272,218	$ 318,113	$ 406,555	$ 387,847	$ 1,673,805	$ 1,384,733	$ 1,330,354
Long-Lived Assets	497,375				411,743				497,375	411,743
North America [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									1,655,219	1,366,470	1,313,917
Long-Lived Assets	488,125				401,276				488,125	401,276
Other Countries [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net sales									18,586	18,263	$ 16,437
Long-Lived Assets	$ 9,250				$ 10,467				$ 9,250	$ 10,467

Supplemental Disclosures of C_3

Supplemental Disclosures of Cash Flow Information - Supplemental Disclosures Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Supplemental Cash Flow Elements [Abstract]
Interest	$ 41,290	$ 15,679	$ 17,890
Income taxes	8,710	29,841	24,510
Redeemable convertible preferred stock dividend	359	134	134
Purchases of plant, property, and equipment included in accounts payable	1,588	1,255	1,258
ESOP distributions in common stock	13,109	8,609	11,566
Lease obligation retired upon disposition of leased assets	$ 799	$ 578	636
Contribution of net accounts receivable to the South American Joint Venture			2,785
Payable recorded for business acquisition			$ 300

Quarterly Financial Informati_3

Quarterly Financial Information - Summary of Quarterly Financial Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 370,768	$ 393,424	$ 495,905	$ 413,708	$ 272,218	$ 318,113	$ 406,555	$ 387,847	$ 1,673,805	$ 1,384,733	$ 1,330,354
Gross profit	108,755	123,358	146,524	(62,158)	59,504	72,399	95,373	99,691	316,479	326,967	302,481
Net income (loss)	3,533	23,659	8,462	(227,451)	1,893	16,550	29,372	33,651	(191,797)	81,466	64,792
Net income (loss) attributable to ADS	$ 2,305	$ 23,288	$ 7,589	$ (226,356)	$ 1,010	$ 15,812	$ 28,670	$ 32,280	$ (193,174)	$ 77,772	$ 62,007	$ 62,007
Net (loss) income per share
Basic	$ 0.01	$ 0.28	$ 0.10	$ (4.06)	$ 0.01	$ 0.25	$ 0.45	$ 0.51	$ (3.21)	$ 1.23	$ 1	$ 1
Diluted	$ 0.01	$ 0.28	$ 0.10	$ (4.06)	$ 0.01	$ 0.25	$ 0.45	$ 0.51	$ (3.21)	$ 1.22	$ 0.99	$ 0.99

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) - $ / shares	3 Months Ended	12 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Subsequent Event [Line Items]
Cash dividend declared		$ 1.36	$ 0.32	$ 0.28
Scenario, Forecast [Member]
Subsequent Event [Line Items]
Cash dividend declared	$ 0.09
Dividend payable date	Jun. 15, 2020
Dividend payable, date of record	Jun. 1, 2020

Schedule II - Consolidated Va_2

Schedule II - Consolidated Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Valuation And Qualifying Accounts [Abstract]
Balance at beginning of period	$ 7,653	$ 6,826	$ 10,431
Charged to costs and expenses	(24)	1,154	503
Charged to other accounts	(234)	(65)	(391)
Deductions	(2,360)	(262)	(3,717)
Balance at end of period	$ 5,035	$ 7,653	$ 6,826

Schedule II - Consolidated Va_3

Schedule II - Consolidated Valuation and Qualifying Accounts (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2017
Valuation And Qualifying Accounts Disclosure [Line Items]
Valuation allowances and reserves, due to acquisition	$ 0.4
South American Joint Venture [Member]
Valuation And Qualifying Accounts Disclosure [Line Items]
Allowance for doubtful accounts	$ 3	$ 3