Airgas 10-K 10 May 16 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Mar. 31, 2016	May. 06, 2016	Sep. 30, 2015
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Mar. 31, 2016
Amendment Flag	false
Entity Registrant Name	AIRGAS INC
Trading Symbol	ARG
Entity Central Index Key	804,212
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--03-31
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 5.8
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Common Stock, Shares Outstanding		72,807,594

Consolidated Statements of Earn

Consolidated Statements of Earnings - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Net sales	$ 5,313,777	$ 5,304,885	$ 5,072,537
Costs and Expenses:
Cost of products sold (excluding depreciation)	2,301,598	2,355,875	2,247,574
Selling, distribution and administrative expenses	2,042,754	1,978,674	1,889,123
Merger costs and other special charges (Notes 2 and 18)	35,967	0	0
Depreciation	318,552	297,710	275,461
Amortization (Note 8)	34,195	31,348	29,845
Total costs and expenses	4,733,066	4,663,607	4,442,003
Operating Income	580,711	641,278	630,534
Interest expense, net (Note 15)	(60,071)	(62,232)	(73,698)
Loss on the extinguishment of debt (Note 10)	0	0	(9,150)
Other income, net	9,077	5,075	4,219
Earnings before income taxes	529,717	584,121	551,905
Income taxes (Note 6)	(192,217)	(216,035)	(201,121)
Net Earnings	$ 337,500	$ 368,086	$ 350,784
Net Earnings Per Common Share (Note 16):
Basic earnings per share	$ 4.60	$ 4.93	$ 4.76
Diluted earnings per share	$ 4.54	$ 4.85	$ 4.68
Weighted Average Shares Outstanding:
Basic	73,422	74,702	73,623
Diluted	74,377	75,851	74,910

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Net earnings	$ 337,500	$ 368,086	$ 350,784
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	(3,712)	(15,708)	(4,235)
Reclassification of hedging loss included in net earnings (Note 11)	259	517	517
Other comprehensive income (loss), before tax	(3,453)	(15,191)	(3,718)
Net tax expense of other comprehensive income items	(96)	(191)	(191)
Other comprehensive income (loss), net of tax	(3,549)	(15,382)	(3,909)
Comprehensive income	$ 333,951	$ 352,704	$ 346,875

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Current Assets
Cash	$ 55,809	$ 50,724
Trade receivables, less allowances for doubtful accounts of $26,959 and $27,016 at March 31, 2016 and 2015, respectively	667,399	708,227
Inventories, net (Note 5)	459,521	474,070
Deferred income tax asset, net (Note 6)	69,908	58,072
Prepaid expenses and other current assets	131,561	124,591
Total current assets	1,384,198	1,415,684
Plant and equipment at cost (Note 7)	5,559,041	5,305,059
Less accumulated depreciation	(2,468,498)	(2,353,293)
Plant and equipment, net	3,090,543	2,951,766
Goodwill (Note 8)	1,364,770	1,313,644
Other intangible assets, net (Note 8)	248,172	244,519
Other non-current assets	47,273	47,997
Total assets	6,134,956	5,973,610
Current Liabilities
Accounts payable, trade	165,781	206,187
Accrued expenses and other current liabilities (Note 9)	348,688	346,879
Short-term debt (Note 10)	383,258	325,871
Current portion of long-term debt (Note 10)	250,107	250,110
Total current liabilities	1,147,834	1,129,047
Long-term debt, excluding current portion (Note 10)	1,954,820	1,748,662
Deferred income tax liability, net (Note 6)	894,344	854,574
Other non-current liabilities	$ 92,660	$ 89,741
Commitments and contingencies (Notes 17 and 18)
Stockholders’ Equity (Note 13)
Preferred stock, 20,030 shares authorized, no shares issued or outstanding at March 31, 2016 and 2015	$ 0	$ 0
Common stock, par value $0.01 per share, 200,000 shares authorized, 87,795 and 87,554 shares issued at March 31, 2016 and 2015, respectively	878	876
Capital in excess of par value	914,692	853,800
Retained earnings	2,377,843	2,231,026
Accumulated other comprehensive loss	(18,402)	(14,853)
Treasury stock, 15,151 and 12,197 shares at cost at March 31, 2016 and 2015, respectively	(1,229,713)	(919,263)
Total stockholders’ equity	2,045,298	2,151,586
Total liabilities and stockholders’ equity	$ 6,134,956	$ 5,973,610

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Allowance for doubtful accounts receivable	$ 26,959	$ 27,016
Preferred stock, shares authorized	20,030,000	20,030,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	87,795,000	87,554,000
Treasury stock, shares	15,151,000	12,197,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Capital In Excess of Par Value [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]
Total stockholders' equity at period start date at Mar. 31, 2013	$ 1,536,983	$ 871	$ 729,850	$ 1,861,395	$ 4,438	$ (1,059,571)
Common stock, issued at period start date, shares at Mar. 31, 2013		87,135
Treasury stock at period start date, shares at Mar. 31, 2013						(14,077)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	350,784			350,784
Foreign currency translation adjustments	(4,235)				(4,235)
Reclassification of hedging loss included in net earnings (Note 11)	517				517
Net tax expense of other comprehensive income items	(191)				(191)
Treasury stock reissuances in connection with stock options exercised (Note 14)	38,310		0			$ 61,185
Treasury stock reissued at lower than repurchase price for stock options exercised (Note 14)				(22,875)
Treasury stock reissuances in connection with stock options exercised, shares (Note 14)						813
Dividends paid on common stock (Note 13)	(141,461)			(141,461)
Excess tax benefit associated with the exercise of stock options	13,668		13,668
Shares issued in connection with the Employee Stock Purchase Plan, shares (Note 14)		218
Shares issued in connection with the Employee Stock Purchase Plan (Note 14)	17,313	$ 3	17,310
Stock-based compensation expense (Note 14)	28,961		28,961
Total stockholders' equity at period end date at Mar. 31, 2014	1,840,649	$ 874	789,789	2,047,843	529	$ (998,386)
Common stock, issued at period end date, shares at Mar. 31, 2014		87,353
Treasury stock at period end date, shares at Mar. 31, 2014						(13,264)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	368,086			368,086
Foreign currency translation adjustments	(15,708)				(15,708)
Reclassification of hedging loss included in net earnings (Note 11)	517				517
Net tax expense of other comprehensive income items	(191)				(191)
Treasury stock reissuances in connection with stock options exercised (Note 14)	54,279		(1,368)			$ 76,033
Treasury stock reissued at lower than repurchase price for stock options exercised (Note 14)				(20,386)
Treasury stock reissuances in connection with stock options exercised, shares (Note 14)						1,026
Reissuance of treasury stock for acquisition (Note 4)	4,458		1,368			$ 3,090
Reissuance of treasury stock for acquisition, shares (Note 4)						41
Dividends paid on common stock (Note 13)	(164,517)			(164,517)
Excess tax benefit associated with the exercise of stock options	16,045		16,045
Shares issued in connection with the Employee Stock Purchase Plan, shares (Note 14)		201
Shares issued in connection with the Employee Stock Purchase Plan (Note 14)	17,941	$ 2	17,939
Stock-based compensation expense (Note 14)	30,027		30,027
Total stockholders' equity at period end date at Mar. 31, 2015	$ 2,151,586	$ 876	853,800	2,231,026	(14,853)	$ (919,263)
Common stock, issued at period end date, shares at Mar. 31, 2015	87,554	87,554
Treasury stock at period end date, shares at Mar. 31, 2015	(12,197)					(12,197)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net earnings	$ 337,500			337,500
Foreign currency translation adjustments	(3,712)				(3,712)
Reclassification of hedging loss included in net earnings (Note 11)	259				259
Net tax expense of other comprehensive income items	(96)				(96)
Treasury stock reissuances in connection with stock options exercised (Note 14)	48,957		0			$ 64,256
Treasury stock reissued at lower than repurchase price for stock options exercised (Note 14)				(15,299)
Treasury stock reissuances in connection with stock options exercised, shares (Note 14)						810
Dividends paid on common stock (Note 13)	(175,384)			(175,384)
Excess tax benefit associated with the exercise of stock options	13,522		13,522
Shares issued in connection with the Employee Stock Purchase Plan, shares (Note 14)		241
Shares issued in connection with the Employee Stock Purchase Plan (Note 14)	19,615	$ 2	19,613
Stock-based compensation expense (Note 14)	27,757		27,757
Purchase of treasury stock (Note 13), shares						(3,764)
Purchase of treasury stock (Note 13)	(374,706)					$ (374,706)
Total stockholders' equity at period end date at Mar. 31, 2016	$ 2,045,298	$ 878	$ 914,692	$ 2,377,843	$ (18,402)	$ (1,229,713)
Common stock, issued at period end date, shares at Mar. 31, 2016	87,795	87,795
Treasury stock at period end date, shares at Mar. 31, 2016	(15,151)					(15,151)

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended												12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Common stock cash dividends paid per share	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.55	$ 0.55	$ 0.55	$ 0.55	$ 0.48	$ 0.48	$ 0.48	$ 0.48	$ 2.40	$ 2.20	$ 1.92

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
CASH FLOWS FROM OPERATING ACTIVITIES
Net earnings	$ 337,500	$ 368,086	$ 350,784
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation	318,552	297,710	275,461
Amortization	34,195	31,348	29,845
Deferred income taxes	27,190	32,841	(6,869)
Gain on sales of plant and equipment	(5,033)	(3,137)	(1,264)
Stock-based compensation expense	27,757	30,027	28,961
Loss on the extinguishment of debt	0	0	9,150
Changes in assets and liabilities, excluding effects of business acquisitions and divestitures:
Trade receivables, net	42,867	(925)	20,030
Inventories, net	18,983	5,091	2,291
Prepaid expenses and other current assets	(8,753)	(31,935)	41,408
Accounts payable, trade	(42,852)	4,954	4,732
Accrued expenses and other current liabilities	(3,590)	(3,377)	(4,463)
Other, net	(2,881)	(12,646)	(5,206)
Net cash provided by operating activities	743,935	718,037	744,860
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(456,899)	(468,789)	(354,587)
Proceeds from sales of plant and equipment	25,521	23,083	15,483
Business acquisitions and holdback settlements	(101,704)	(51,382)	(203,529)
Other, net	2,556	325	(951)
Net cash used in investing activities	(530,526)	(496,763)	(543,584)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in short-term debt	55,756	(62,776)	387,352
Proceeds from borrowings of long-term debt	472,659	317,423	135,861
Repayment of long-term debt	(266,414)	(415,907)	(636,587)
Financing costs	3,311	5,445	0
Premium paid on redemption of senior subordinated notes	0	0	(7,676)
Purchase of treasury stock	(374,706)	0	(8,127)
Proceeds from the exercise of stock options	49,521	54,280	38,310
Stock issued for the Employee Stock Purchase Plan	19,615	17,940	17,313
Excess tax benefit realized from the exercise of stock options	13,522	16,045	13,668
Dividends paid to stockholders	(175,384)	(164,517)	(141,461)
Change in cash overdraft and other	418	2,846	(16,754)
Net cash used in financing activities	(208,324)	(240,111)	(218,101)
Change in cash	5,085	(18,837)	(16,825)
Cash - Beginning of period	50,724	69,561	86,386
Cash - End of period	$ 55,809	$ 50,724	$ 69,561

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (a) Description of the Business Airgas, Inc., together with its subsidiaries (“Airgas” or the “Company”), became a publicly traded company on the New York Stock Exchange in 1986 . Since its inception, the Company has made approximately 480 acquisitions to become one of the nation’s leading suppliers of industrial, medical and specialty gases, and hardgoods, such as welding equipment and related products. Airgas is a leading U.S. producer of atmospheric gases, carbon dioxide, dry ice and nitrous oxide, one of the largest U.S. suppliers of safety products, and a leading U.S. supplier of refrigerants, ammonia products and process chemicals. The Company markets its products and services through multiple sales channels, including branch-based sales representatives, retail stores, strategic customer account programs, telesales, catalogs, e-Business and independent distributors. Approximately 17,000 associates work in more than 1,100 locations, including branches, retail stores, gas fill plants, specialty gas labs, production facilities and distribution centers. (b) Basis of Presentation The consolidated financial statements include the accounts of Airgas, Inc. and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation. The Company has made estimates and assumptions relating to the reporting of assets and liabilities and disclosure of contingent assets and liabilities to prepare these consolidated financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”). Estimates are used for, but not limited to, determining the net carrying value of trade receivables, inventories, plant and equipment, goodwill, other intangible assets, asset retirement obligations, business and health insurance reserves, loss contingencies and deferred tax assets. Actual results could differ from those estimates. (c) Cash and Cash Overdraft On a daily basis, available funds are swept from depository accounts into a concentration account and used to repay borrowings under the Company’s commercial paper program. Cash principally represents the balance of customer checks that have not yet cleared through the banking system and become available to be swept into the concentration account, and deposits made subsequent to the daily cash sweep. The Company does not fund its disbursement accounts for checks it has written until the checks are presented to the bank for payment. Cash overdrafts represent the balance of outstanding checks and are classified with other current liabilities. There are no compensating balance requirements or other restrictions on the transfer of cash associated with the Company’s depository accounts. (d) Allowance for Doubtful Accounts The Company maintains an allowance for doubtful accounts, which includes sales returns, sales allowances and bad debts. The allowance adjusts the carrying value of trade receivables for the estimate of accounts that will ultimately not be collected. An allowance for doubtful accounts is generally established as trade receivables age beyond their due dates, whether as bad debts or as sales returns and allowances. As past due balances age, higher valuation allowances are established, thereby lowering the net carrying value of receivables. The amount of valuation allowance established for each past-due period reflects the Company’s historical collections experience, including that related to sales returns and allowances, as well as current economic conditions and trends. The Company also qualitatively establishes valuation allowances for specific problem accounts and bankruptcies, and other accounts that the Company deems relevant for specifically identified allowances. The amounts ultimately collected on past due trade receivables are subject to numerous factors including general economic conditions, the condition of the receivable portfolios assumed in acquisitions, the financial condition of individual customers and the terms of reorganization for accounts exiting bankruptcy. Changes in these conditions impact the Company’s collection experience and may result in the recognition of higher or lower valuation allowances. (e) Inventories Inventories are stated at the lower of cost or net realizable value. Cost is determined using the first-in, first-out (“FIFO”) and average-cost methods. Substantially all of the inventories are finished goods. (f) Plant and Equipment Plant and equipment are initially stated at cost. Long-lived assets, including plant and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the recorded values cannot be recovered from the undiscounted future cash flows. For impairment testing purposes, long-lived assets are grouped with other assets and liabilities at the lowest level for which independent identifiable cash flows are determinable. When the book value of an asset or group of assets exceeds the associated undiscounted expected future cash flows, it is considered to be potentially impaired and is written down to fair value, which is determined based on either discounted future cash flows or appraised values. The Company also leases property, plant and equipment, principally under operating leases. Rent expense for operating leases, which may have escalating rentals or rent holidays, is recorded on a straight-line basis over the respective lease terms. The Company determines depreciation expense using the straight-line method based on the estimated useful lives of the related assets. The Company uses accelerated depreciation methods for tax purposes where appropriate. Depreciation expense is recognized on the Company’s plant and equipment in the consolidated statement of earnings line item “Depreciation.” The Company capitalizes the interest cost associated with the development and construction of significant new plant and equipment and depreciates that amount over the lives of the related assets. Capitalized interest recorded for construction in progress during each of the years in the three-year period ended March 31, 2016 was not material. (g) Computer Software The Company capitalizes certain costs incurred to purchase or develop computer software for internal use. These costs include purchased software packages, payments to vendors and consultants for the development, implementation or modification of purchased software packages for Company use, payroll and related costs for employees associated with internal-use software projects, interest costs incurred in developing software for internal use, and software costs that allow for access or conversion of old data by new internal-use software. Capitalized computer software costs are included within plant and equipment on the Company’s consolidated balance sheets and depreciated over the estimated useful life of the computer software, which is generally three to ten years. (h) Goodwill and Other Intangible Assets Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. The Company is required to test goodwill associated with each of its reporting units for impairment at least annually and whenever events or circumstances indicate that it is more likely than not that goodwill may be impaired. The Company performs its annual goodwill impairment test as of October 31 of each year. Other intangible assets primarily consist of non-competition agreements and customer relationships resulting from business acquisitions. Both non-competition agreements and customer relationships are recorded based on their acquisition date fair values. Non-competition agreements are amortized using the straight-line method over the respective terms of the agreements. Customer relationships are amortized using the straight-line method over their estimated useful lives, which range from seven to 25 years. The determination of the estimated benefit periods associated with customer relationships is based on an analysis of historical customer sales attrition information and other customer-related factors at the date of acquisition. There are no expected residual values related to the Company’s other intangible assets. The Company evaluates the estimated benefit periods and recoverability of its other intangible assets when facts and circumstances indicate that the lives may not be appropriate and/or the carrying values of the asset group containing other intangible assets may not be recoverable through the projected undiscounted future cash flows of the group. If the carrying value of the asset group containing other intangible assets is not recoverable, impairment is measured as the amount by which the carrying value exceeds its estimated fair value. Fair value is determined using discounted cash flows or other techniques. (i) Deferred Financing Costs Financing costs related to the issuance of long-term debt are deferred and included in prepaid expenses and other current assets or in other non-current assets, depending upon the classification of the debt to which the costs relate. Deferred financing costs are amortized as interest expense over the term of the related debt instrument. (j) Asset Retirement Obligations The fair value of a liability for an asset retirement obligation is recognized in the period during which the asset is placed in service. The fair value of the liability is estimated using projected discounted cash flows. In subsequent periods, the retirement obligation is accreted to its future value, which is the estimate of the obligation at the asset retirement date. When the asset is placed in service, a corresponding retirement asset equal to the fair value of the retirement obligation is also recorded as part of the carrying amount of the related long-lived asset and depreciated over the asset’s useful life. The majority of the Company’s asset retirement obligations are related to the restoration costs associated with returning plant and bulk tank sites to their original condition upon termination of long-term leases or supply agreements. The Company’s asset retirement obligations totaled $22.8 million and $20.4 million at March 31, 2016 and 2015 , respectively, and are reflected within other non-current liabilities on the Company’s consolidated balance sheets. (k) Loss Contingencies Liabilities for loss contingencies arising from claims, assessments, litigation and other sources are recorded when it is probable that a liability has been incurred and the amount of the claim, assessment or damages can be reasonably estimated. The Company maintains business insurance programs with deductible limits, which cover workers’ compensation, business automobile and general liability claims. The Company accrues estimated losses using actuarial models and assumptions based on historical loss experience. The actuarial calculations used to estimate business insurance reserves are based on numerous assumptions, some of which are subjective. The Company will adjust its business insurance reserves, if necessary, in the event future loss experience differs from historical loss patterns. (l) Income Taxes Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases, and operating loss carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and operating loss carryforwards are expected to be recovered, settled or utilized. 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. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. The Company recognizes the benefit of an income tax position only if it is more likely than not (greater than 50%) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position. Otherwise, no benefit is recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Additionally, the Company accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. Interest and penalties are classified as income tax expense in the consolidated statements of earnings. (m) Foreign Currency Translation The functional currency of the Company’s foreign operations is the applicable local currency. The translation of foreign currencies into U.S. dollars is performed for balance sheet accounts using current exchange rates in effect at the balance sheet date and for revenue and expense accounts using average exchange rates during each reporting period. The gains or losses resulting from such translations are included in stockholders’ equity as a component of accumulated other comprehensive loss. Gains and losses arising from foreign currency transactions are reflected in the consolidated statements of earnings as incurred. (n) Treasury Stock The Company records repurchases of its common stock for treasury at cost. Upon the reissuance of the Company’s common stock from treasury, differences between the proceeds from reissuance and the average cost of the treasury stock are credited or charged to capital in excess of par value to the extent of prior credits related to the reissuance of treasury stock. If no such credits exist, the differences are charged to retained earnings. (o) Concentrations of Credit Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of trade receivables. Concentrations of credit risk are limited due to the Company’s large number of customers and their dispersion across many industries primarily throughout North America. Credit terms granted to customers are generally net 30 days. (p) Derivative Instruments and Hedging Activities The Company manages its exposure to changes in market interest rates through the occasional use of interest rate derivative instruments, when deemed appropriate. The Company’s involvement with derivative instruments has been limited to interest rate swap and treasury rate lock agreements used to manage well-defined interest rate risk exposures. An interest rate swap is a contractual exchange of interest payments between two parties. A standard interest rate swap involves the payment of a fixed rate times a notional amount by one party in exchange for receiving a floating rate times the same notional amount from the other party. As interest rates change, the difference to be paid or received is accrued and recognized as interest expense or income over the life of the agreement. Treasury rate lock agreements are used to fix the interest rate related to forecasted debt issuances. Interest rate swap and treasury rate lock agreements are not entered into for trading purposes. When the Company has derivative instruments outstanding, it monitors its positions as well as the credit ratings of its counterparties, including the potential for non-performance by the counterparties. The Company recognizes outstanding derivative instruments as either assets or liabilities at fair value on the consolidated balance sheet. Interest rate contracts have traditionally been designated as hedges and recorded at fair value, with changes in fair value recognized in either accumulated other comprehensive income or in the carrying value of the hedged portions of fixed-rate debt, as applicable. Gains and losses on derivative instruments representing hedge ineffectiveness were recognized immediately in the respective year’s earnings. (q) Revenue Recognition Revenue from sales of gases and hardgoods products is recognized when the product is shipped, the sales price is fixed or determinable and collectability is reasonably assured. Rental fees on cylinders, cryogenic liquid containers, bulk gas storage tanks and other equipment are recognized when earned. For contracts that contain multiple deliverables, principally product supply agreements for gases and container rental, revenue is recognized for each deliverable as a separate unit of accounting, with selling prices derived from Company specific or third-party evidence. For cylinder lease agreements in which rental fees are collected in advance, revenues are deferred and recognized over the respective terms of the lease agreements. Amounts billed for sales tax, value added tax or other transactional taxes imposed on revenue-producing transactions are presented on a net basis and are not recognized as revenue. (r) Cost of Products Sold (Excluding Depreciation) Cost of products sold (excluding depreciation) for the Distribution business segment includes the cost of direct materials, freight-in and maintenance costs associated with cylinders, cryogenic liquid containers and bulk tanks. Cost of products sold (excluding depreciation) related to gases produced by the Company’s air separation facilities includes direct manufacturing expenses, such as direct labor, power and overhead. Cost of products sold (excluding depreciation) for the All Other Operations business segment principally consists of direct material costs, freight-in and direct manufacturing expenses, such as direct labor, power and overhead. (s) Selling, Distribution and Administrative Expenses Selling, distribution and administrative expenses consist of labor and overhead associated with the purchasing, marketing and distribution of the Company’s products, as well as costs associated with a variety of administrative functions such as legal, treasury, accounting and tax, and facility-related expenses. (t) Shipping and Handling Fees and Distribution Costs The Company recognizes delivery and freight charges to customers as elements of net sales. Costs of third-party freight-in are recognized as cost of products sold (excluding depreciation). The majority of the costs associated with the distribution of the Company’s products, which include labor and overhead associated with filling, warehousing and delivery by Company and third-party vehicles, are reflected in selling, distribution and administrative expenses and were $918 million , $889 million and $850 million for the fiscal years ended March 31, 2016 , 2015 and 2014 , respectively. The Company conducts multiple operations out of the same facilities and does not allocate facility-related expenses to each operational function. Accordingly, there is no facility-related expense in the distribution costs disclosed above. Depreciation expense associated with the Company’s delivery fleet of $33 million , $32 million and $32 million was recognized in depreciation for the fiscal years ended March 31, 2016 , 2015 and 2014 , respectively. (u) Stock-based Compensation The Company grants stock-based compensation awards in connection with its equity incentive and employee stock purchase plans. Stock-based compensation expense is generally recognized on a straight-line basis over the stated vesting period for each award, with accelerated vesting for retirement-eligible employees in accordance with the provisions of the equity incentive plan. See Note 14 for additional disclosures relating to stock-based compensation.

Merger Agreement

Merger Agreement	12 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Merger Agreement [Text Block]	MERGER AGREEMENT On November 17, 2015, the Company announced that it had entered into a definitive agreement for the acquisition of the Company by L’Air Liquide, S.A. (“Air Liquide”) in a merger pursuant to an Agreement and Plan of Merger, dated as of November 17, 2015, by and among the Company, Air Liquide and AL Acquisition Corporation (“Merger Sub”), an indirect wholly owned subsidiary of Air Liquide (the “Merger Agreement”). The Merger Agreement provides that, among other things and subject to the terms and conditions thereof, Merger Sub will be merged with and into the Company (the “Merger”) with the Company continuing as the surviving corporation in the Merger as an indirect wholly owned subsidiary of Air Liquide. As consideration for the Merger, each outstanding share of common stock of the Company, par value $0.01 (the “Common Stock”), will automatically be converted into the right to receive $143 in cash at the effective time of the Merger (the “Effective Time”), excluding treasury stock owned by the Company or shares owned by Air Liquide or any of its subsidiaries, which will be canceled. The closing of the Merger is subject to customary closing conditions, including the adoption of the Merger Agreement by the affirmative vote of the holders of at least a majority of all outstanding shares of Common Stock, which occurred on February 23, 2016, and the receipt of antitrust approval, which is yet to be received. In connection with the Merger, the Company has incurred $29 million of merger-related costs during fiscal 2016, primarily consisting of legal, advisory and other professional fees in connection with the Merger. These costs are included in the “Merger costs and other special charges” line item of the Company’s consolidated statement of earnings.

Accounting and Disclosure Chang

Accounting and Disclosure Changes	12 Months Ended
	Mar. 31, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Accounting And Disclosure Changes	ACCOUNTING AND DISCLOSURE CHANGES In April 2014, the Financial Accounting Standards Board ( “ FASB ” ) issued new guidance on the reporting of discontinued operations. The new guidance limits the presentation of discontinued operations to disposals that represent a strategic shift with a major effect on an entity’s operations and financial results. In contrast, many disposals under previous standards, which may have been more routine in nature and not changed an entity’s strategy, were reported in discontinued operations. The new guidance also requires disclosures around both disposals qualifying for discontinued operations as well as significant disposals that are not considered discontinued operations. The Company adopted the new guidance effective April 1, 2015. The guidance did not have an impact on the Company’s consolidated financial statements and related disclosures upon adoption. In July 2015, the FASB issued new guidance that changes the measurement principle for inventory from the lower of cost or market to the lower of cost or net realizable value. The amendments in this guidance do not apply to inventory that is measured using last-in, first-out (“LIFO”) or the retail inventory method; rather, the amendments apply to all other inventory, which includes inventory that is measured using first-in, first-out (“FIFO”) or average cost. Within the scope of this new guidance, an entity should measure inventory at the lower of cost or net realizable value. Net realizable value is defined as the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation, which is consistent with existing GAAP. The Company early adopted the new guidance effective July 1, 2015. The guidance did not have a material impact on the Company’s consolidated financial statements and related disclosures upon adoption. In September 2015, the FASB issued new guidance simplifying the accounting for measurement-period adjustments with respect to business combinations. The amendments in this guidance eliminate the requirement for an acquirer to retrospectively account for adjustments that occur to provisional amounts recognized at the acquisition date during the measurement period following an acquisition. The new guidance requires that an acquirer recognize adjustments to provisional amounts identified during the measurement period in the reporting period in which the adjustment amounts are determined, with disclosure of the amounts recognized in the current period that would have been recognized in prior reporting periods based on the date of the acquisition. The Company early adopted the new guidance effective September 30, 2015. The guidance did not have a material impact on the Company’s consolidated financial statements and related disclosures upon adoption. In May 2014, the FASB issued new guidance on the accounting for revenue from contracts with customers, which requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. The new guidance will replace most existing GAAP revenue recognition guidance when it becomes effective. In August 2015, the FASB deferred the effective date of the new guidance by one year to December 15, 2017 for annual reporting periods beginning after that date and permitted early adoption of the standard, but not before the original effective date of December 15, 2016. With the deferral, the new standard is effective for the Company for annual and interim reporting periods beginning on April 1, 2018, with early adoption permitted one year prior. The standard permits the use of either the retrospective or cumulative effect transition method. The Company is evaluating the transition method alternatives and the effect that the new guidance will have on its consolidated financial statements and related disclosures. In February 2015, the FASB issued new guidance changing the analysis that a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The new guidance changes the way reporting enterprises evaluate whether (a) they should consolidate limited partnerships and similar entities, (b) fees paid to a decision maker or service provider are variable interests in a variable interest entity (“VIE”), and (c) variable interests in a VIE held by related parties of the reporting enterprise require the reporting enterprise to consolidate the VIE. The Company adopted the new guidance effective April 1, 2016. The guidance did not impact the Company’s consolidated financial statements upon adoption. In April 2015, the FASB issued new guidance simplifying the financial statement presentation of debt issuance costs. The new guidance specifies that debt issuance costs related to a recognized term debt obligation shall be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The existing recognition and measurement guidance for debt issuance costs is not affected by the new guidance. In August 2015, the FASB issued a clarification that debt issuance costs related to line-of-credit arrangements can continue to be reflected as deferred assets in the balance sheet consistent with existing GAAP, or can be presented net of the associated debt obligations. The Company adopted the new guidance effective April 1, 2016 and will apply the guidance on a retrospective basis in its future financial statements. The adoption of the new guidance did not have a material impact on the Company’s consolidated financial statements. In April 2015, the FASB issued new guidance on customer’s accounting for fees paid in a cloud computing arrangement. The amendments to existing GAAP provide guidance to customers about whether a cloud computing arrangement includes a software license. The new guidance clarifies that if a cloud computing arrangement includes a software license, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If the arrangement does not include a software license, the customer should account for the arrangement as a service contract. The Company adopted the new guidance effective April 1, 2016 on a prospective basis. The new guidance may be applied either prospectively to all arrangements entered into or materially modified after the effective date, or on a retrospective basis. The adoption of the new guidance did not have a material impact on the Company’s consolidated financial statements. In November 2015, the FASB issued new guidance simplifying the balance sheet classification of deferred taxes. The new guidance requires that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The current requirement that deferred tax liabilities and assets of a tax-paying component of an entity be offset and presented as a single amount is not affected by the new guidance. The new guidance is effective for the Company on April 1, 2017, with early adoption permitted as of the beginning of an interim or annual reporting period. The new guidance may be applied either prospectively to all deferred tax liabilities and assets or retrospectively to all periods presented. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements and related disclosures. In January 2016, the FASB issued new guidance related to the recognition and measurement of financial assets and liabilities. The new guidance makes targeted improvements to GAAP impacting equity investments (other than those accounted for under the equity method or consolidated), financial liabilities accounted for under the fair value election, and presentation and disclosure requirements for financial instruments, among other changes. The new guidance is effective for the Company on April 1, 2018, with early adoption prohibited other than for certain provisions. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements and related disclosures. In February 2016, the FASB issued new guidance related to the recognition of lease assets and lease liabilities. The new guidance requires lessees to recognize almost all leases on their balance sheet as a right-of-use asset and a lease liability, other than leases that meet the definition of a short- term lease, and requires expanded disclosures about leasing arrangements. The recognition, measurement, and presentation of expenses and cash flows arising from a lease by a lessee have not significantly changed from the current guidance. Lessor accounting is similar to the current guidance, but updated to align with certain changes to the lessee model and the new revenue recognition standard. The new guidance is effective for the Company on April 1, 2019, with early adoption permitted. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements and related disclosures. In March 2016, the FASB issued new guidance that includes targeted improvements to the accounting for employee stock-based compensation. The updates in the guidance include changes in the income tax consequences, balance sheet classification and cash flow statement reporting of stock-based payment transactions. The new guidance will impact the Company’s accounting for awards under its equity incentive plan (see Note 14). Among other changes, excess tax benefits that are currently recognized as part of stockholders’ equity will impact income tax expense in the statement of earnings under the new guidance, and will also be classified with other income tax cash flows in operating activities in the statement of cash flows rather than as currently reported in financing activities. The new guidance is effective for the Company on April 1, 2017, with early adoption permitted. The Company is evaluating the impact that the new guidance will have on its consolidated financial statements and related disclosures.

Acquisitions

Acquisitions	12 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Acquisitions	ACQUISITIONS Acquisitions are recorded using the acquisition method of accounting and accordingly, results of their operations are included in the Company’s consolidated financial statements from the effective date of each respective acquisition. The Company negotiates the respective purchase prices of acquired businesses based on the expected cash flows to be derived from their operations after integration into the Company’s existing distribution, production and service networks. The acquisition purchase price for each business is allocated based on the fair values of the assets acquired and liabilities assumed. Management estimates the fair values of acquired intangible assets other than goodwill using the income approach (i.e. discounted cash flows), and plant and equipment using either the cost or market approach, depending on the type of fixed asset. Fiscal 2016 During fiscal 2016 , the Company acquired 18 businesses with historical annual sales of approximately $85 million . Transaction and other integration costs incurred in fiscal 2016 were $2.3 million and were included in selling, distribution and administrative expenses in the Company’s consolidated statement of earnings. These acquisitions contributed approximately $45 million in net sales in fiscal 2016 . Purchase price allocations for certain businesses most recently acquired during fiscal 2016 are primarily based on provisional fair values and are subject to revision as the Company finalizes appraisals and other analyses. Final determination of the fair values may result in further adjustments to the values presented below. The following table summarizes the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2016 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 58,018 $ 44,014 $ 102,032 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 8,532 $ 2,228 $ 10,760 Plant and equipment 11,701 13,246 24,947 Other intangible assets 24,057 12,769 36,826 Current liabilities (7,216 ) (4,247 ) (11,463 ) Non-current liabilities (3,856 ) (3,997 ) (7,853 ) Total identifiable net assets 33,218 19,999 53,217 Goodwill 24,800 24,015 48,815 $ 58,018 $ 44,014 $ 102,032 ____________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. The fair value of trade receivables acquired with fiscal 2016 acquisitions was $6.1 million , with gross contractual amounts receivable of $6.9 million . Goodwill associated with fiscal 2016 acquisitions was $48.6 million , of which $44.4 million is deductible for income tax purposes. Goodwill largely consists of expected synergies resulting from the acquisitions, including increased distribution density and enhanced capabilities that will facilitate the sale of industrial, medical and specialty gases, and related supplies, the addition of businesses that offer products and services complementary to the Company’s existing portfolio, and enhanced geographical coverage abroad to strengthen the Company’s welder and generator rental business. Other intangible assets related to fiscal 2016 acquisitions represent customer relationships and non-competition agreements and amounted to $29.3 million and $7.6 million , respectively. See Note 8 for further information on goodwill and other intangible assets. Pro Forma Operating Results The following table provides unaudited pro forma results of operations for fiscal 2016 and 2015 , as if fiscal 2016 acquisitions had occurred on April 1, 2014 . The pro forma results were prepared from financial information obtained from the sellers of the businesses, as well as information obtained during the due diligence process associated with the acquisitions. The unaudited pro forma results reflect certain adjustments related to the acquisitions, such as increased depreciation and amortization expense resulting from the stepped-up basis to fair value of assets acquired and adjustments to reflect the Company’s borrowing and tax rates. The pro forma operating results do not include any anticipated synergies related to combining the businesses. Accordingly, such pro forma operating results were prepared for comparative purposes only and do not purport to be indicative of what would have occurred had the acquisitions been made as of April 1, 2014 or of results that may occur in the future. Unaudited Years Ended March 31, (In thousands, except per share amounts) 2016 2015 Net sales $ 5,335,812 $ 5,388,313 Net earnings 338,408 372,975 Diluted earnings per share $ 4.55 $ 4.92 Fiscal 2015 During fiscal 2015 , the Company acquired 14 businesses with historical annual sales of approximately $55 million . Transaction and other integration costs incurred in fiscal 2015 were $1.7 million and were included in selling, distribution and administrative expenses in the Company’s consolidated statement of earnings. These acquisitions contributed approximately $27 million in net sales in fiscal 2015 . The following table summarizes, as of March 31, 2015 , the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2015 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 50,774 $ 1,053 $ 51,827 Airgas, Inc. common stock (b) 4,458 — 4,458 Fair value of total consideration transferred $ 55,232 $ 1,053 $ 56,285 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 9,705 $ 3 $ 9,708 Plant and equipment 13,824 — 13,824 Other intangible assets 15,122 1,040 16,162 Current liabilities (5,765 ) (50 ) (5,815 ) Non-current liabilities (4,526 ) — (4,526 ) Total identifiable net assets 28,360 993 29,353 Goodwill 26,872 60 26,932 $ 55,232 $ 1,053 $ 56,285 __________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. (b) Represents 41,060 shares of Airgas, Inc. common stock issued in connection with a single acquisition. The fair value of the shares issued as part of the consideration for the acquisition was determined based on the closing sales price of Airgas, Inc. common stock on the acquisition date. The fair value of trade receivables acquired with fiscal 2015 acquisitions was $6.2 million , with gross contractual amounts receivable of $7.0 million . Goodwill associated with fiscal 2015 acquisitions was $25.1 million , of which $20.9 million is deductible for income tax purposes. Goodwill largely consists of expected synergies resulting from the acquisitions, including increased distribution density and enhanced capabilities that will facilitate the sale of industrial, medical and specialty gases and related supplies. Other intangible assets related to fiscal 2015 acquisitions represent customer relationships and non-competition agreements, and amounted to $11.3 million and $4.8 million , respectively. Pro Forma Operating Results The following table provides unaudited pro forma results of operations for fiscal 2015 and 2014 , as if fiscal 2015 acquisitions had occurred on April 1, 2013 . The pro forma operating results were prepared for comparative purposes only and do not purport to be indicative of what would have occurred had the acquisitions been made as of April 1, 2013 or of results that may occur in the future. Unaudited Years Ended March 31, (In thousands, except per share amounts) 2015 2014 Net sales $ 5,327,458 $ 5,123,949 Net earnings 368,305 351,941 Diluted earnings per share $ 4.86 $ 4.70 Fiscal 2014 During fiscal 2014 , the Company acquired eleven businesses with historical annual sales of approximately $82 million .The largest of these businesses was The Encompass Gas Group, Inc. (“Encompass”), headquartered in Rockford, Illinois. With eleven locations in Illinois, Wisconsin, and Iowa, Encompass was one of the largest privately-owned suppliers of industrial, medical, and specialty gases and related hardgoods in the United States, generating approximately $55 million in sales in calendar 2012. Transaction and other integration costs incurred in fiscal 2014 were $1.5 million and were included in selling, distribution and administrative expenses in the Company’s consolidated statement of earnings. These acquisitions contributed approximately $33 million in net sales in fiscal 2014 . The following table summarizes, as of March 31, 2014 , the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2014 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 204,957 $ 413 $ 205,370 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 14,631 $ 9 $ 14,640 Plant and equipment 48,919 (746 ) 48,173 Other intangible assets 60,190 — 60,190 Current liabilities (6,088 ) 1,366 (4,722 ) Non-current liabilities (8,321 ) — (8,321 ) Total identifiable net assets 109,331 629 109,960 Goodwill 95,626 (216 ) 95,410 $ 204,957 $ 413 $ 205,370 ________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. The fair value of trade receivables acquired with fiscal 2014 acquisitions was $8.9 million , with gross contractual amounts receivable of $9.4 million . Goodwill associated with fiscal 2014 acquisitions was $93.3 million , of which $89.7 million is deductible for income tax purposes. Goodwill largely consists of expected synergies resulting from the acquisitions, including the expansion of geographical coverage that will facilitate the sale of industrial, medical and specialty gases and related supplies. Other intangible assets related to fiscal 2014 acquisitions represent customer relationships and non-competition agreements, and amounted to $55.8 million and $4.3 million , respectively.

Inventories, Net

Inventories, Net	12 Months Ended
	Mar. 31, 2016
Inventory, Net [Abstract]
Inventories, Net	INVENTORIES, NET Inventories, net, consist of: (In thousands) March 31, 2016 March 31, 2015 Hardgoods $ 309,897 $ 311,453 Gases 149,624 162,617 $ 459,521 $ 474,070

Income Taxes

Income Taxes	12 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Earnings before income taxes were derived from the following sources: Years Ended March 31, (In thousands) 2016 2015 2014 United States $ 527,100 $ 572,182 $ 539,063 Foreign 2,617 11,939 12,842 $ 529,717 $ 584,121 $ 551,905 Income tax expense consists of: Years Ended March 31, (In thousands) 2016 2015 2014 Current: Federal $ 148,585 $ 163,774 $ 184,308 Foreign 1,029 2,010 4,561 State 15,413 17,410 19,121 165,027 183,194 207,990 Deferred: Federal 30,792 24,499 (4,722 ) Foreign (197 ) 2,604 (1,127 ) State (3,405 ) 5,738 (1,020 ) 27,190 32,841 (6,869 ) $ 192,217 $ 216,035 $ 201,121 Significant differences between taxes computed at the federal statutory rate and the provision for income taxes were: Years Ended March 31, 2016 2015 2014 Taxes at U.S. federal statutory rate 35.0 % 35.0 % 35.0 % Increase (decrease) in income taxes resulting from: State income taxes, net of federal benefit 1.5 % 2.6 % 2.1 % Domestic production activities deduction (1.2 )% (1.0 )% (1.0 )% Other, net 1.0 % 0.4 % 0.3 % 36.3 % 37.0 % 36.4 % The tax effects of cumulative temporary differences and carryforwards that gave rise to the significant portions of the deferred tax assets and liabilities were as follows: March 31, (In thousands) 2016 2015 Deferred Tax Assets: Inventories $ 25,936 $ 27,697 Deferred rental income 17,670 17,986 Insurance reserves 12,410 14,157 Litigation settlement and other reserves 2,330 3,132 Asset retirement obligations 8,279 7,553 Stock-based compensation 36,357 33,538 Other 35,787 19,876 Net operating loss carryforwards 11,070 12,061 Valuation allowance (1,141 ) (671 ) 148,698 135,329 Deferred Tax Liabilities: Plant and equipment (732,503 ) (711,840 ) Intangible assets (227,809 ) (207,690 ) Other (12,822 ) (12,301 ) (973,134 ) (931,831 ) Net deferred tax liability $ (824,436 ) $ (796,502 ) Current deferred tax assets and current deferred tax liabilities have been netted for presentation purposes. Non-current deferred tax assets and non-current deferred tax liabilities have also been netted. Deferred tax assets and liabilities are reflected in the Company’s consolidated balance sheets as follows: March 31, (In thousands) 2016 2015 Current deferred income tax asset, net $ 69,908 $ 58,072 Non-current deferred income tax liability, net (894,344 ) (854,574 ) Net deferred tax liability $ (824,436 ) $ (796,502 ) The Company has recorded tax benefits amounting to $13.5 million , $16.0 million and $13.7 million in the years ended March 31, 2016 , 2015 and 2014 , respectively, resulting from the exercise of stock options. This benefit has been recorded in capital in excess of par value. The Company has recorded deferred tax assets related to the expected future tax benefits of net operating losses of $11.1 million and $12.1 million as of March 31, 2016 and 2015 , respectively. State net operating loss carryforwards expire at various times through 2036 . Foreign net operating losses are available to offset future income taxes over an indefinite period. U.S. income taxes have not been provided on approximately $97 million of undistributed earnings of non-U.S. subsidiaries because it is the Company’s intention to continue to reinvest these earnings in those subsidiaries to support their growth. Due to the timing and circumstances of repatriation of such earnings, if any, it is not practicable to determine the unrecognized deferred tax liability relating to such amounts. As of March 31, 2016 , the Company has unrecognized state tax benefits of approximately $20.9 million , which were recorded in other non-current liabilities, and a related $8.3 million of federal tax assets associated with those state tax benefits recorded in non-current deferred tax assets. If recognized, all of the unrecognized tax benefits and related interest and penalties would reduce tax expense. The Company does not anticipate significant changes in the amount of unrecognized income tax benefits over the next year. A reconciliation of the beginning and ending amount of unrecognized net income tax benefits, including penalties associated with uncertain tax positions, is as follows: March 31, (In thousands) 2016 2015 Beginning unrecognized net income tax benefits $ 20,983 $ 18,224 Additions for current year tax positions 3,845 3,565 Additions for tax positions of prior years 187 1,288 Reductions for tax positions of prior years (3,306 ) (1,646 ) Reductions for settlements with taxing authorities — (234 ) Reductions as a result of expiration of applicable statutes of limitations (787 ) (214 ) Ending unrecognized net income tax benefits $ 20,922 $ 20,983 Interest and penalties recognized for the years ended March 31, 2016 , 2015 and 2014 were classified as income tax expense in the Company’s consolidated statements of earnings and were not material. Consistent with past practice, the Company will continue to record interest and penalties associated with uncertain tax positions in income tax expense. The Company had approximately $3.8 million and $4.7 million for the payment of interest and penalties accrued at March 31, 2016 and 2015 , respectively. The Company files income tax returns in the United States and foreign jurisdictions. The Company also files income tax returns in every state which imposes corporate income tax. The Company is not under examination by the IRS or in any significant foreign, state or local tax jurisdictions. With limited exceptions, the Company is no longer subject to U.S. federal, state and local, or foreign income tax examinations by tax authorities for years before fiscal 2012.

Plant and Equipment

Plant and Equipment	12 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Plant and Equipment	PLANT AND EQUIPMENT The major classes of plant and equipment, at cost, are as follows: March 31, Depreciable Lives (Yrs) 2016 2015 (In thousands) Land and land improvements — $ 246,820 $ 225,721 Buildings and improvements 25 634,816 581,076 Cylinders 30 1,504,566 1,461,600 Bulk tank stations 10 to 30 (Average 17) 846,344 789,881 Rental equipment 2 to 10 496,383 466,833 Machinery and equipment 7 to 10 1,057,142 988,857 Computers, furniture and fixtures 3 to 10 296,408 338,316 Transportation equipment 3 to 15 366,221 369,034 Construction in progress — 110,341 83,741 $ 5,559,041 $ 5,305,059

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Other Intangible Assets	GOODWILL AND OTHER INTANGIBLE ASSETS Goodwill Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. The valuations of assets acquired and liabilities assumed from certain recent acquisitions are based on preliminary estimates of fair value and are subject to revision as the Company finalizes appraisals and other analysis. Changes in the carrying amount of goodwill by business segment for fiscal 2016 and 2015 were as follows: (In thousands) Distribution Business Segment All Other Operations Business Segment Total Balance at March 31, 2014 $ 1,092,728 $ 197,168 $ 1,289,896 Acquisitions (a) 26,872 60 26,932 Other adjustments, including foreign currency translation (3,031 ) (153 ) (3,184 ) Balance at March 31, 2015 1,116,569 197,075 1,313,644 Acquisitions (a) 24,800 24,015 48,815 Other adjustments, including foreign currency translation 2,337 (26 ) 2,311 Balance at March 31, 2016 $ 1,143,706 $ 221,064 $ 1,364,770 ____________________ (a) Includes acquisitions completed during the respective year and adjustments made to prior year acquisitions. Annual Test for Goodwill Impairment The Company is required to test goodwill associated with each of its reporting units for impairment at least annually and whenever events or circumstances indicate that it is more likely than not that goodwill may be impaired. The Company performs its annual goodwill impairment test as of October 31 of each year. At October 31, 2015, the Company had 21 reporting units in the Distribution business segment and 6 reporting units in the All Other Operations business segment, each of which constitutes an operating segment for purposes of the Company’s segment reporting. GAAP provides that prior to performing the traditional two-step goodwill impairment test, the Company is permitted to first perform a qualitative assessment about the likelihood of the carrying value of a reporting unit exceeding its fair value, referred to as the “Step 0” assessment. The Step 0 assessment requires the evaluation of certain events and circumstances such as macroeconomic conditions, industry and market considerations, cost factors and overall financial performance, as well as company and reporting unit-specific items. After performing the Step 0 assessment, should the Company determine that it is more likely than not that the fair value of a reporting unit is less than its carrying amount, it is required to perform the prescribed two-step goodwill impairment test to identify the potential goodwill impairment and measure the amount of the goodwill impairment loss, if any, to be recognized for that reporting unit. However, if the Company concludes otherwise based on the Step 0 assessment, the two-step goodwill impairment test is not required. The Step 0 assessment can be applied to none, some or all of the Company’s reporting units in any period, and the Company may also bypass the Step 0 assessment for any reporting unit in any period and proceed directly to performing the first step of the two-step goodwill impairment test for the given reporting unit. For the October 31, 2015 goodwill impairment test, the Company bypassed the option to perform the Step 0 assessment for all of its reporting units as a periodic refresh of its reporting units’ fair values from the application of the qualitative Step 0 assessment in prior years. The determination to proceed to the first step of the two-step goodwill impairment test at October 31, 2015 was based on an evaluation of relevant events and circumstances, including the length of time since the Company’s most recent calculation of the fair value of its reporting units. The fair values of the Company’s reporting units evaluated using the qualitative Step 0 assessment in the prior year were all substantially in excess of their respective carrying amounts in the Company’s prior Step 1 analysis. The Company determined the estimated fair value of each of its reporting units as of October 31, 2015 using a discounted cash flow model and compared those values to the carrying value of each of the respective reporting units. Significant assumptions used in the cash flow model include sales growth rates and profit margins based on specific reporting unit business plan, future capital expenditures, working capital needs, and discount and perpetual growth rates. The discount rates used to estimate the fair value of the individual reporting unit exceeded the Company’s weighted average cost of capital as a whole, as the discount rate used for this purpose assigns a higher risk premium to the smaller individual reporting units. The perpetual growth rate assumed in the discounted cash flow model was in line with the long-term growth rate as measured by the U.S. Gross Domestic Product and the industry’s long-term rate of growth. In addition to Company and reporting unit-specific growth targets, general economic conditions, the long-term economic outlook for the U.S. economy, and market conditions affecting borrowing costs and returns on equity all influence the estimated fair value of each of the Company’s reporting units. The Company’s methodology used for valuing its reporting units for the purpose of its goodwill impairment test is consistent with prior valuations. The Company’s annual goodwill impairment test at October 31, 2015 indicated that the fair values of all of its reporting units substantially exceeded their respective carrying amounts. Other Intangible Assets Other intangible assets by major class are as follows: March 31, 2016 March 31, 2015 (In thousands) Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships 17 $ 368,096 $ (138,467 ) $ 229,629 17 $ 345,805 $ (120,321 ) $ 225,484 Non-competition agreements 6 45,171 (26,776 ) 18,395 6 43,204 (24,335 ) 18,869 Other 200 (52 ) 148 200 (34 ) 166 $ 413,467 $ (165,295 ) $ 248,172 $ 389,209 $ (144,690 ) $ 244,519 As the Company’s other intangible assets amortize and reach the end of their respective amortization periods, the fully amortized balances are removed from the gross carrying and accumulated amortization amounts. Amortization expense related to the Company’s other intangible assets for fiscal 2016 and 2015 was $32.7 million and $30.0 million , respectively. Estimated future amortization expense by fiscal year is as follows: fiscal 2017 - $31.8 million ; 2018 - $29.5 million ; 2019 - $27.4 million ; 2020 - $25.9 million ; 2021 - $22.2 million ; and $111.4 million thereafter.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Mar. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Accrued Expenses And Other Current Liabilities	ACCRUED EXPENSES AND OTHER CURRENT LIABILITIES Accrued expenses and other current liabilities include: (In thousands) March 31, 2016 March 31, 2015 Accrued payroll and employee benefits $ 81,107 $ 98,547 Business insurance reserves (a) 48,176 49,934 Taxes other than income taxes 22,160 22,863 Cash overdraft 72,282 71,537 Deferred rental revenue 34,440 34,538 Accrued interest 10,855 12,860 Other accrued expenses and current liabilities 79,668 56,600 $ 348,688 $ 346,879 ____________________ (a) With respect to the business insurance reserves above, the Company had corresponding insurance receivables of $9.9 million at March 31, 2016 and $11.6 million at March 31, 2015 , which are included within the “Prepaid expenses and other current assets” line item on the Company’s consolidated balance sheets. The insurance receivables represent the balance of probable claim losses in excess of the Company’s deductible for which the Company is fully insured.

Indebtedness

Indebtedness	12 Months Ended
	Mar. 31, 2016
Debt Instruments [Abstract]
Indebtedness	INDEBTEDNESS Total debt consists of: (In thousands) March 31, 2016 March 31, 2015 Short-term Money market loans $ — $ — Commercial paper 383,258 325,871 Short-term debt $ 383,258 $ 325,871 Long-term Trade receivables securitization $ 330,000 $ 295,000 Revolving credit borrowings - U.S. — — Revolving credit borrowings - Multi-currency 70,259 48,332 Revolving credit borrowings - France 6,088 6,277 Senior notes, net 1,798,282 1,648,608 Other long-term debt 298 555 Total long-term debt 2,204,927 1,998,772 Less current portion of long-term debt (250,107 ) (250,110 ) Long-term debt, excluding current portion $ 1,954,820 $ 1,748,662 Total debt $ 2,588,185 $ 2,324,643 Money Market Loans The Company has an agreement with a financial institution to provide access to short-term advances not to exceed $35 million that expires on December 27, 2016 . The agreement may be further extended subject to renewal provisions contained in the agreement. The advances may be for one to six months with rates at a fixed spread over the corresponding London Interbank Offering Rate (“LIBOR”) . At March 31, 2016 , there were no advances outstanding under the agreement. The Company also has an agreement with another financial institution that provides access to additional short-term advances not to exceed $35 million that expires on July 31, 2016 . The agreement may be extended subject to renewal provisions contained in the agreement. The advances are generally overnight or for up to seven days. The amount, term and interest rate of an advance are established through mutual agreement with the financial institution when the Company requests such an advance . At March 31, 2016 , there were no advances outstanding under the agreement. Commercial Paper The Company participates in a $1 billion commercial paper program supported by its $1 billion Credit Facility (see below). This program allows the Company to obtain favorable short-term borrowing rates with maturities that vary, but will generally not exceed 90 days from the date of issue , and is classified as short-term debt. At maturity, the commercial paper balances are often rolled over rather than repaid or refinanced, depending on the Company’s cash and liquidity positions. The Company has used proceeds from commercial paper issuances for general corporate purposes. At March 31, 2016 , $383 million was outstanding under the commercial paper program and the average interest rate on these borrowings was 0.79% . There was $326 million outstanding under the commercial paper program at March 31, 2015 . Trade Receivables Securitization The Company participates in a securitization agreement with four commercial bank conduits to which it sells qualifying trade receivables on a revolving basis (the “Securitization Agreement”). The Company’s sale of qualified trade receivables is accounted for as a secured borrowing under which qualified trade receivables collateralize amounts borrowed from the commercial bank conduits. Trade receivables that collateralize the Securitization Agreement are held in a bankruptcy-remote special purpose entity, which is consolidated for financial reporting purposes and represents the Company’s only variable interest entity. Qualified trade receivables in the amount of the outstanding borrowing under the Securitization Agreement are not available to the general creditors of the Company. The maximum amount available under the Securitization Agreement is $330 million , with the outstanding borrowings bearing interest at a rate of approximately LIBOR plus 75 basis points. On July 24, 2015 , the Company entered into the Sixth Amendment and Joinder (the “Sixth Amendment”) to the Third Amended and Restated Receivables Purchase Agreement (the “Securitization Agreement”), which increased the maximum amount of borrowings available under the Securitization Agreement from $295 million to $330 million . The Sixth Amendment also increased the number of participating banks from three to four . On December 4, 2015 , the Company entered into the Seventh Amendment to the Securitization Agreement which extended the expiration date of the Securitization Agreement from December 5, 2017 to December 5, 2018 . There were no other material changes to the Securitization Agreement as a result of the Seventh Amendment. On March 23, 2016 , the Company entered into the Eighth Amendment to the Securitization Agreement which revises the change in control provisions contained in the Securitization Agreement to exclude the previously-announced proposed acquisition of the Company by L’Air Liquide, S.A., and makes certain other changes to the financial reporting requirements of the Company contained in the Securitization Agreement in anticipation of the Proposed Acquisition. The maximum amount of borrowings available to the Company under the Securitization Agreement remained unchanged as a result of the Eighth Amendment. Senior Credit Facility The Company participates in a $1 billion Amended and Restated Credit Facility (the “Credit Facility”). The Credit Facility consists of an $875 million U.S. dollar revolving credit line, with a $100 million letter of credit sublimit and a $75 million swingline sublimit, and a $125 million (U.S. dollar equivalent) multi-currency revolving credit line. The maturity date of the Credit Facility is November 18, 2019 . Under the circumstances described in the Credit Facility, the revolving credit line may be increased by an additional $500 million , provided that the multi-currency revolving credit line may not be increased by more than an additional $50 million . As of March 31, 2016 , the Company had $70 million of borrowings under the Credit Facility, all of which were under the multi-currency revolver. There were no borrowings under the U.S. dollar revolver at March 31, 2016 . The Company also had outstanding U.S. letters of credit of $51 million issued under the Credit Facility. U.S. dollar revolver borrowings bear interest at the LIBOR plus 125 basis points. The multi-currency revolver bears interest based on a rate of 125 basis points over the Euro currency rate applicable to each foreign currency borrowing. As of March 31, 2016 , the average interest rate on the multi-currency revolver was 1.9% . In addition to the borrowing spread of 125 basis points for U.S. dollar and multi-currency revolver borrowings, the Company pays a commitment (or unused) fee on the undrawn portion of the Credit Facility equal to 15 basis points per annum. At March 31, 2016 , the financial covenant of the Credit Facility did not restrict the Company’s ability to borrow on the unused portion of the Credit Facility. The Credit Facility contains customary events of default including, without limitation, failure to make payments, a cross-default to certain other debt, breaches of covenants, breaches of representations and warranties, certain monetary judgments and bankruptcy and ERISA events. At March 31, 2016 , the Company was in compliance with all covenants under all of its debt agreements. In the event of default, repayment of borrowings under the Credit Facility may be accelerated. As of March 31, 2016 , $495 million remained available under the Company’s Credit Facility, after giving effect to the borrowings under the commercial paper program backstopped by the Credit Facility, the outstanding U.S. letters of credit and the borrowings under the multi-currency revolver. The Company also maintains a committed revolving line of credit of up to €8.0 million (U.S. $9.1 million ) to fund its operations in France. These revolving credit borrowings are outside of the Company’s Credit Facility. At March 31, 2016 , these revolving credit borrowings were €5.3 million (U.S. $6.1 million ). The variable interest rates on these revolving credit borrowings are based on the Euro currency rate plus 125 basis points. This revolving credit agreement matures on November 18, 2019 . Senior Notes The Company’s senior notes consisted of the following: (In thousands) Principal Description Coupon Yield Maturity Date Semi-annual Interest Payment Dates March 31, 2016 March 31, 2015 2015 Notes (a) 3.25% 3.283% 10/01/2015 April 1 and October 1 $ — $ 250,000 2016 Notes (c) 2.95% 2.980% 06/15/2016 June 15 and December 15 250,000 250,000 2018 Notes 1.65% 1.685% 02/15/2018 February 15 and August 15 325,000 325,000 2020 A Notes 2.375% 2.392% 02/15/2020 February 15 and August 15 275,000 275,000 2020 B Notes (b) 3.05% 3.092% 08/01/2020 February 1 and August 1 400,000 — 2022 Notes 2.90% 2.913% 11/15/2022 May 15 and November 15 250,000 250,000 2024 Notes 3.65% 3.673% 07/15/2024 January 15 and July 15 300,000 300,000 1,800,000 1,650,000 Less: unamortized discount (1,718 ) (1,392 ) Senior notes, net $ 1,798,282 $ 1,648,608 ____________________ (a) On September 14, 2015, the Company redeemed in full its 2015 Notes senior notes originally due to mature on October 1, 2015. (b) On August 11, 2015, the Company issued the 2020 B Notes. The net proceeds from the sale of the 2020 Notes were used for general corporate purposes, including to fund acquisitions, to repay indebtedness and to repurchase shares pursuant to the Company’s stock repurchase program. Interest payments on the 2020 Notes commenced on February 1, 2016. (c) The 2016 Notes are included within the “Current portion of long-term debt” line item on the Company’s consolidated balance sheet based on the maturity date. The 2016, 2018, 2020 A, 2020 B, 2022 and 2024 Notes (collectively, the “Senior Notes”) contain covenants that could restrict the incurrence of liens and limit sale and leaseback transactions. Additionally, the Company has the option to redeem the Senior Notes prior to their maturity, in whole or in part, at 100% of the principal plus any accrued but unpaid interest or at the applicable make-whole premium. Debt Extinguishment Charge On October 2, 2013, the Company redeemed its $215 million 7.125% senior subordinated notes originally due to mature on October 1, 2018 in full at a price of 103.563% . A loss on the early extinguishment of debt of $9.1 million was recognized during the year ended March 31, 2014 related to the redemption premium and the write-off of unamortized debt issuance costs. Aggregate Long-term Debt Maturities The aggregate maturities of long-term debt at March 31, 2016 are as follows: (In thousands) Debt Maturities (a) Years Ending March 31, 2017 $ 250,118 2018 325,175 2019 330,004 2020 351,348 2021 400,000 Thereafter 550,000 $ 2,206,645 ____________________ (a) Outstanding borrowings under the Securitization Agreement at March 31, 2016 are reflected as maturing at the agreement’s expiration in December 2018 . The Senior Notes are reflected in the debt maturity schedule at their maturity values rather than their carrying values, which are net of aggregate discounts of $1.7 million at March 31, 2016 .

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	12 Months Ended
	Mar. 31, 2016
General Discussion of Derivative Instruments and Hedging Activities [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES Cash Flow Hedges In anticipation of the issuance of the 2015 Notes, the Company entered into a treasury rate lock agreement in July 2010 with a notional amount of $100 million that matured in September 2010 . The treasury rate lock agreement was designated as a cash flow hedge of the semi-annual interest payments associated with the forecasted issuance of the 2015 Notes. When the treasury rate lock agreement matured, the Company realized a loss of $2.6 million ( $1.6 million after tax) which was reported as a component within accumulated other comprehensive income (“AOCI”) and is being reclassified into earnings over the term of the 2015 Notes. For the years ended March 31, 2016 , 2015 and 2014 , $259 thousand , $517 thousand and $517 thousand respectively, of the loss on the treasury rate lock was reclassified to interest expense during each period (see Note 13 for details). At March 31, 2016 , there was no remaining estimated loss recorded in AOCI on the treasury rate lock agreement as the 2015 Notes matured in October 2015. Fair Value Hedges The Company previously had five variable interest rate swap agreements outstanding with a notional amount of $300 million , which were designated as fair value hedges. These variable interest rates swaps were used to effectively convert the Company’s $300 million of fixed rate 2.85% senior notes (the “2013 Notes”) to variable rate debt. The swap agreements matured on October 1, 2013, coinciding with the maturity date of the Company’s 2013 Notes. For these derivative instruments designated as fair value hedges, the Company recorded the gain or loss on the derivatives (interest rate swaps) as well as the offsetting gain or loss on the hedged item attributable to the hedged risk (the 2013 Notes) in interest expense in the consolidated statements of earnings for the respective years. The net gain or loss recorded in earnings as a result of hedge ineffectiveness related to the designated fair value hedges was immaterial for the year ended March 31, 2014. Tabular Disclosure There were no outstanding derivative instruments on the Company’s consolidated balance sheets at March 31, 2016 or 2015, nor any derivative instruments used by the Company during the years ended March 31, 2016 or 2015. The following table illustrates the effect of derivative instruments in fair value hedging relationships on the Company’s earnings. See Note 13 for the tabular presentation of derivative instruments in cash flow hedging relationships related to the treasury rate lock agreement. Location of Gain (Loss) Recognized in Pre-tax Income Amount of Gain (Loss) Recognized in Pre-Tax Income (In thousands) Year Ended March 31, 2014 Derivatives in Fair Value Hedging Relationships Change in fair value of variable interest rate swaps Interest expense, net $ (2,490 ) Change in carrying value of 2013 Notes Interest expense, net 2,496 Net effect Interest expense, net $ 6

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Assets and liabilities recorded at fair value are classified based upon the level of judgment associated with the inputs used to measure their fair value. The hierarchical levels related to the subjectivity of the valuation inputs are defined as follows: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities at the measurement date. • Level 2 inputs are inputs, other than quoted prices included within Level 1, that are observable, directly or indirectly through corroboration with observable market data at the measurement date. • Level 3 inputs are unobservable inputs that reflect management’s best estimate of the assumptions (including assumptions about risk) that market participants would use in pricing the asset or liability at the measurement date. The carrying value of cash, trade receivables, other current receivables, trade payables and other current liabilities (e.g., deposit liabilities, cash overdrafts, etc.) approximates fair value based on the short-term maturity of these financial instruments. Assets and Liabilities Measured at Fair Value on a Recurring Basis Assets and liabilities measured at fair value on a recurring basis at March 31, 2016 and 2015 are categorized in the tables below based on the lowest level of significant input to the valuation. During the periods presented, there were no transfers between fair value hierarchical levels. Balance at Quoted prices in active markets Level 1 Significant other observable inputs Level 2 Significant unobservable inputs Level 3 (In thousands) March 31, 2016 Assets: Deferred compensation plan assets $ 17,731 $ 17,731 $ — $ — Liabilities: Deferred compensation plan liabilities $ 17,731 $ 17,731 $ — $ — Balance at Quoted prices in active markets Level 1 Significant other observable inputs Level 2 Significant unobservable inputs Level 3 (In thousands) March 31, 2015 Assets: Deferred compensation plan assets $ 16,288 $ 16,288 $ — $ — Liabilities: Deferred compensation plan liabilities $ 16,288 $ 16,288 $ — $ — The following is a general description of the valuation methodologies used for financial assets and liabilities measured at fair value: Deferred compensation plan assets and corresponding liabilities — The Company’s deferred compensation plan assets consist of open-ended mutual funds (Level 1) and are included within other non-current assets on the consolidated balance sheets. The Company’s deferred compensation plan liabilities are equal to the plan’s assets and are included within other non-current liabilities on the consolidated balance sheets. Gains or losses on the deferred compensation plan assets are recognized as other income, net, while gains or losses on the deferred compensation plan liabilities are recognized as compensation expense in the consolidated statements of earnings. See Note 19 for additional information on the Company’s deferred compensation plan. Fair Value of Debt The carrying value of debt, which is reported on the Company’s consolidated balance sheets, generally reflects the cash proceeds received upon its issuance, net of subsequent repayments, plus the impact of the Company’s fair value hedges as applicable. The fair values of the fixed rate notes disclosed in the following table were determined based on quoted prices from the broker/dealer market, observable market inputs for similarly termed treasury notes adjusted for the Company’s credit spread and inputs management believes a market participant would use in determining imputed interest for obligations without a stated interest rate (Level 2). The fair values of the revolving credit borrowings, securitized receivables and commercial paper approximate their carrying values (see Note 10). Carrying Value at Fair Value at Carrying Value at Fair Value at (In thousands) March 31, 2016 March 31, 2016 March 31, 2015 March 31, 2015 3.25% senior notes due 2015 $ — $ — $ 249,962 $ 252,520 2.95% senior notes due 2016 249,988 250,543 249,918 254,953 1.65% senior notes due 2018 324,796 324,942 324,688 323,921 2.375% senior notes due 2020 274,834 276,859 274,791 274,821 3.05% senior notes due 2020 399,328 410,416 — — 2.90% senior notes due 2022 249,815 250,555 249,787 249,028 3.65% senior notes due 2024 299,520 308,082 299,462 310,500

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Mar. 31, 2016
Stockholders' Equity Note [Abstract]
Stockholders' Equity	STOCKHOLDERS’ EQUITY Common Stock The Company is authorized to issue up to 200 million shares of common stock with a par value of $0.01 per share. At March 31, 2016 , the number of shares of common stock outstanding was 72.6 million , excluding 15.2 million shares of common stock held as treasury stock. At March 31, 2015 , the number of shares of common stock outstanding was 75.4 million , excluding 12.2 million shares of common stock held as treasury stock. Preferred Stock and Redeemable Preferred Stock The Company is authorized to issue up to 20 million shares of preferred stock. Of the 20 million shares authorized, 200 thousand shares have been designated as Series A Junior Participating Preferred Stock, 200 thousand shares have been designated as Series B Junior Participating Preferred Stock and 200 thousand shares have been designated as Series C Junior Participating Preferred Stock (see Stockholder Rights Plan below). At March 31, 2016 and 2015 , no shares of the preferred stock were issued or outstanding. The preferred stock may be issued from time to time by the Company’s Board of Directors in one or more series. The Board of Directors is authorized to fix the dividend rights and terms, conversion rights, voting rights, rights and terms of redemption, liquidation preferences, and any other rights, preferences, privileges and restrictions of any series of preferred stock, and the number of shares constituting such series and designation thereof. Additionally, the Company is authorized to issue 30 thousand shares of redeemable preferred stock. At March 31, 2016 and 2015 , no shares of redeemable preferred stock were issued or outstanding. Dividends The Company paid its stockholders regular quarterly cash dividends of $0.60 , $0.55 and $0.48 per share at the end of each of its fiscal quarters during the years ended March 31, 2016 , 2015 and 2014 , respectively. Future dividend declarations and associated amounts paid will depend upon the Company’s earnings, financial condition, loan covenants, capital requirements and other factors deemed relevant by management and the Company’s Board of Directors. Any future dividend increases would be subject to certain limitations as described in the Merger Agreement. Stockholder Rights Plan Effective May 8, 2007, the Company’s Board of Directors adopted a stockholder rights plan (the “2007 Rights Plan”). Pursuant to the 2007 Rights Plan, the Board of Directors declared a dividend distribution of one right for each share of common stock. Each right entitles the holder to purchase from the Company one ten-thousandth of a share of Series C Junior Participating Preferred Stock at an initial exercise price of $230 per share. The 2007 Rights Plan is intended to assure that all of the Company’s stockholders receive fair and equal treatment in the event of any proposed takeover of the Company and to protect stockholders’ interests in the event the Company is confronted with partial tender offers or other coercive or unfair takeover tactics. Rights become exercisable after ten days following the acquisition by a person or group of 15% (or 20% in the case of Peter McCausland and certain of his affiliates) or more of the Company’s outstanding common stock, or ten business days (or later if determined by the Board of Directors in accordance with the plan) after the announcement of a tender offer or exchange offer to acquire 15% (or 20% in the case of Peter McCausland and certain of his affiliates) or more of the outstanding common stock. If such a person or group acquires 15% or more (or 20% or more, as the case may be) of the common stock, each right (other than such person’s or group’s rights, which will become void) will entitle the holder to purchase, at the exercise price, common stock having a market value equal to twice the exercise price. In certain circumstances, the rights may be redeemed by the Company at an initial redemption price of 0.0001 per right. If not redeemed, the rights will expire on May 8, 2017. On November 17, 2015, the Company entered into an amendment (the “Rights Amendment”) to the stockholder rights plan (the “Rights Plan”) originally dated May 8, 2007. The Rights Amendment modifies the existing terms of the Rights Plan by lowering the beneficial ownership threshold for triggering the Rights Plan from 15% of Airgas’ common stock to 10% . Any party that beneficially owns 10% or more of the Company’s common stock at the time of the public announcement of the Rights Amendment will not trigger the Rights Plan unless that party increases its beneficial ownership in the Company’s common stock or exercises any options, rights, warrants, etc. for shares of the Company’s common stock. Additionally, the Rights Amendment modifies and amends the Rights Plan to provide that the Merger Agreement and any agreements or transactions associated with the foregoing will not result in a stock acquisition date (as defined therein), a distribution date (as defined therein) or any other separation of rights from the underlying common stock. There were no other significant changes to the Company’s Rights Plan as a result of the Rights Amendment. Stock Repurchase Program On May 28, 2015, the Company announced plans to purchase up to $500 million of Airgas, Inc. common stock under a stock repurchase program approved by the Company’s Board of Directors. Airgas may repurchase shares from time to time for cash in open market transactions or in privately-negotiated transactions in accordance with applicable federal securities laws. The Company will determine the timing and the amount of any repurchases based on its evaluation of market conditions, share price, and other factors. The stock repurchase program has no pre-established closing date. However, stock repurchases are currently suspended in accordance with the Merger Agreement (see Note 2). From the announcement date of the program through March 31, 2016 , the Company repurchased 3.8 million shares on the open market at an average price of $99.54 , but did not repurchase any shares during the six months ended March 31, 2016 . At March 31, 2016 , $125 million was available for additional share repurchases under the program. Comprehensive Income The Company’s comprehensive income was $334 million , $353 million and $347 million for the years ended March 31, 2016 , 2015 and 2014 , respectively. Comprehensive income consists of net earnings, foreign currency translation adjustments, net gain or loss on derivative instruments and the net tax expense or benefit of other comprehensive income items. Net tax expense or benefit of comprehensive income items pertains to the Company’s derivative instruments only, as foreign currency translation adjustments relate to permanent investments in foreign subsidiaries. The net gain or loss on derivative instruments reflects valuation adjustments for changes in interest rates, as well as cash settlements with the counterparties and reclassification adjustments to income. See Note 11 for further information on derivative instruments. The following table presents the gross and net changes in the balances within each component of AOCI for each of the years in the three-year period ended March 31, 2016 . (In thousands) Foreign Currency Translation Adjustments Treasury Rate Lock Agreement Total Accumulated Other Comprehensive Income (Loss) Balance at March 31, 2013 $ 5,253 $ (815 ) $ 4,438 Other comprehensive income (loss) before reclassifications (4,235 ) — (4,235 ) Amounts reclassified from AOCI (a) — 517 517 Tax effect of other comprehensive income items — (191 ) (191 ) Other comprehensive income (loss), net of tax (4,235 ) 326 (3,909 ) Balance at March 31, 2014 1,018 (489 ) 529 Other comprehensive income (loss) before reclassifications (15,708 ) — (15,708 ) Amounts reclassified from AOCI (a) — 517 517 Tax effect of other comprehensive income items — (191 ) (191 ) Other comprehensive income (loss), net of tax (15,708 ) 326 (15,382 ) Balance at March 31, 2015 (14,690 ) (163 ) (14,853 ) Other comprehensive income (loss) before reclassifications (3,712 ) — (3,712 ) Amounts reclassified from AOCI (a) — 259 259 Tax effect of other comprehensive income items — (96 ) (96 ) Other comprehensive income (loss), net of tax (3,712 ) 163 (3,549 ) Balance at March 31, 2016 $ (18,402 ) $ — $ (18,402 ) ___________________ (a) The reclassifications out of AOCI were associated with a loss on a treasury rate lock agreement from July 2010 related to the issuance of the Company’s 2015 Notes, which was being reclassified into earnings (interest expense) over the term of the 2015 Notes until their redemption in September 2015. The effects on the respective line items of the consolidated statements of earnings impacted by the reclassifications were not material for the twelve months ended March 31, 2016 , 2015 and 2014 .

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Mar. 31, 2016
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company recognizes stock-based compensation expense for its equity incentive plan and employee stock purchase plan. The following table summarizes stock-based compensation expense recognized by the Company in each of the years in the three-year period ended March 31, 2016 . Years Ended March 31, (In thousands) 2016 2015 2014 Stock-based compensation expense related to: Equity Incentive Plan $ 24,464 $ 25,935 $ 24,892 Employee Stock Purchase Plan - options to purchase stock 3,293 4,092 4,069 27,757 30,027 28,961 Tax benefit (9,850 ) (10,624 ) (10,392 ) Stock-based compensation expense, net of tax $ 17,907 $ 19,403 $ 18,569 2006 Equity Incentive Plan On August 14, 2012, the Company’s stockholders approved the Second Amended and Restated 2006 Equity Incentive Plan (the “2006 Equity Plan”), which included, among other things, a 4.0 million increase in the maximum number of shares available for issuance under the plan. At March 31, 2016 , a total of 11.9 million shares were authorized under the 2006 Equity Plan, as amended, for grants of stock options, stock appreciation rights, restricted stock and restricted stock units to employees, directors and consultants of the Company, of which 2.3 million shares of common stock were available for issuance. Stock options granted to employees vest 25% annually and have a maximum term of eight years. Stock options granted to directors vest and are fully exercisable immediately upon being granted. Fair Value The Company utilizes the Black-Scholes option pricing model to determine the fair value of stock options. The weighted-average grant date fair value of stock options granted during the fiscal years ended March 31, 2016 , 2015 and 2014 was $19.87 , $28.72 and $32.41 , respectively. The following assumptions were used by the Company in valuing the stock options grants issued in each fiscal year: Fiscal 2016 Fiscal 2015 Fiscal 2014 Expected volatility 24.8 % 34.3 % 40.5 % Expected dividend yield 2.31 % 2.06 % 1.95 % Expected term 5.6 years 5.6 years 5.6 years Risk-free interest rate 1.7 % 1.7 % 1.0 % The expected volatility assumption used in valuing stock options was determined based on anticipated changes in the underlying stock price over the expected term using historical daily changes of the Company’s closing stock price. The expected dividend yield was based on the Company’s history and expectation of future dividend payouts. The expected term represents the period of time that the options are expected to be outstanding prior to exercise or forfeiture. The expected term was determined based on historical exercise patterns. The risk-free interest rate was based on U.S. Treasury rates in effect at the time of grant commensurate with the expected term. Summary of Stock Option Activity The following table summarizes the stock option activity during the three years ended March 31, 2016 : Number of Stock Options Weighted-Average Exercise Price Aggregate Intrinsic Value (In thousands) Outstanding at March 31, 2013 5,052,016 $ 60.26 Granted 959,700 $ 102.96 Exercised (817,016 ) $ 47.38 Forfeited (90,276 ) $ 85.04 Outstanding at March 31, 2014 5,104,424 $ 69.91 $ 186,816 Granted 977,500 $ 104.80 Exercised (1,034,325 ) $ 53.49 Forfeited (73,929 ) $ 98.24 Outstanding at March 31, 2015 4,973,670 $ 79.76 $ 131,135 Granted 1,019,675 $ 103.57 Exercised (837,455 ) $ 62.06 Forfeited (91,550 ) $ 101.83 Outstanding at March 31, 2016 5,064,340 $ 87.08 $ 276,296 Vested or expected to vest at March 31, 2016 5,051,024 $ 87.04 $ 275,798 Exercisable at March 31, 2016 2,911,622 $ 75.47 $ 192,649 The aggregate intrinsic value represents the difference between the Company’s closing stock price on the last trading day of each fiscal year and the exercise price of in-the-money stock options multiplied by the number of stock options outstanding or exercisable as of that date. The total intrinsic value of stock options exercised during the years ended March 31, 2016 , 2015 and 2014 was $52.5 million , $60.8 million and $47.0 million , respectively. The weighted-average remaining contractual term of stock options outstanding as of March 31, 2016 was 4.6 years. Common stock to be issued in conjunction with future stock option exercises will be obtained from either new shares or shares from treasury stock. As of March 31, 2016 , $35.3 million of unrecognized non-cash compensation expense related to non-vested stock options is expected to be recognized over a weighted-average vesting period of 1.6 years. Under the terms of the Merger Agreement (see Note 2), all of the stock options outstanding upon the closing of the Merger under the Equity Incentive Plan, whether vested or unvested, would be canceled in consideration for the right of each stock option holder to receive a cash payment equal to the number of stock options held multiplied by the excess of the Merger consideration of $143 per share over the exercise price per share of the Company’s common stock subject to the stock options. Employee Stock Purchase Plan The Amended and Restated Airgas, Inc. 2003 Employee Stock Purchase Plan (“Employee Stock Purchase Plan” or “ESPP”) encourages and assists employees in acquiring an equity interest in the Company. As of March 31, 2016 , the ESPP was authorized to issue up to 5.5 million shares of Company common stock, of which 900 thousand shares were available for issuance at March 31, 2016 . Under the terms of the ESPP, eligible employees may elect to have up to 15% of their annual gross earnings withheld to purchase common stock at 85% of the market value. Employee purchases are limited in any calendar year to an aggregate market value of $25 thousand . Market value under the ESPP is defined as either the closing share price on the New York Stock Exchange as of an employee’s enrollment date or the closing price on the first business day of a fiscal quarter when the shares are purchased, whichever is lower. An employee may lock-in a purchase price for up to 12 months. The ESPP effectively resets at the beginning of each fiscal year at which time employees are re-enrolled in the plan and a new 12 -month purchase price is established. The ESPP is designed to comply with the requirements of Sections 421 and 423 of the Internal Revenue Code. Fair Value Compensation expense is measured based on the fair value of the employees’ option to purchase shares of common stock at the grant date and is recognized over the future periods in which the related employee service is rendered. The fair value per share of employee options to purchase shares under the ESPP was $17.59 , $20.44 and $19.27 for the years ended March 31, 2016 , 2015 and 2014 , respectively. The fair value of the employees’ option to purchase shares of common stock was estimated using the Black-Scholes model. The following assumptions were used by the Company in valuing the employees’ option to purchase shares of common stock under the ESPP: Fiscal 2016 Fiscal 2015 Fiscal 2014 Expected volatility 17.9 % 17.1 % 19.5 % Expected dividend yield 2.60 % 2.07 % 1.96 % Expected term 3 to 9 months 3 to 9 months 3 to 9 months Risk-free interest rate 0.04 % 0.06 % 0.08 % ESPP - Purchase Option Activity The following table summarizes the activity of the ESPP during the three years ended March 31, 2016 : Number of Purchase Options Weighted-Average Exercise Price Aggregate Intrinsic Value (In thousands) Outstanding at March 31, 2013 62,137 $ 68.74 Granted 211,093 $ 82.88 Exercised (218,109 ) $ 79.38 Outstanding at March 31, 2014 55,121 $ 80.77 $ 1,419 Granted 200,030 $ 90.82 Exercised (201,037 ) $ 89.24 Outstanding at March 31, 2015 54,114 $ 86.47 $ 1,063 Granted 187,265 $ 78.93 Exercised (241,379 ) $ 81.26 Outstanding at March 31, 2016 — $ — $ — In accordance with the terms of the Merger Agreement, there were no outstanding purchase options at March 31, 2016 as the January 2016 purchase represented the final purchase under the ESPP, with no further grants of options to purchase common stock under the ESPP. As a result, all compensation expense related to the outstanding purchase options under the ESPP was recognized in full at December 31, 2015, and no additional expense was incurred related to the Company’s ESPP for the remainder of fiscal 2016.

Interest Expense, Net

Interest Expense, Net	12 Months Ended
	Mar. 31, 2016
Interest Expense [Abstract]
Interest Expense, Net	INTEREST EXPENSE, NET Interest expense, net, consists of: Years Ended March 31, (In thousands) 2016 2015 2014 Interest expense $ 62,100 $ 64,191 $ 75,361 Interest and finance charge income (2,029 ) (1,959 ) (1,663 ) $ 60,071 $ 62,232 $ 73,698

Earnings Per Share

Earnings Per Share	12 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings per share is calculated by dividing net earnings by the weighted average number of shares of the Company’s common stock outstanding during the period. Outstanding shares consist of issued shares less treasury stock. Diluted earnings per share is calculated by dividing net earnings by the weighted average common shares outstanding adjusted for the dilutive effect of common stock equivalents related to stock options and the Company’s ESPP. Outstanding stock options that are anti-dilutive are excluded from the Company’s diluted earnings per share computation. There were approximately 1.9 million , 1.7 million and 1.5 million shares covered by outstanding stock options that were not dilutive for the years ended March 31, 2016 , 2015 and 2014 , respectively. The table below presents the computation of basic and diluted weighted average common shares outstanding for the years ended March 31, 2016 , 2015 and 2014 : (In thousands, except per share amounts) Years Ended March 31, Basic Earnings per Share Computation 2016 2015 2014 Numerator: Net earnings $ 337,500 $ 368,086 $ 350,784 Denominator: Basic shares outstanding 73,422 74,702 73,623 Basic earnings per share $ 4.60 $ 4.93 $ 4.76 (In thousands, except per share amounts) Years Ended March 31, Diluted Earnings per Share Computation 2016 2015 2014 Numerator: Net earnings $ 337,500 $ 368,086 $ 350,784 Denominator: Basic shares outstanding 73,422 74,702 73,623 Incremental shares from assumed exercises and conversions: Stock options and options under the Employee Stock Purchase Plan 955 1,149 1,287 Diluted shares outstanding 74,377 75,851 74,910 Diluted earnings per share $ 4.54 $ 4.85 $ 4.68

Leases

Leases	12 Months Ended
	Mar. 31, 2016
Leases [Abstract]
Leases	LEASES The Company leases certain facilities, fleet vehicles and equipment under long-term operating leases with varying terms. Most leases contain renewal options and in some instances, purchase options. Rentals under these operating leases for the years ended March 31, 2016 , 2015 and 2014 totaled approximately $130 million , $121 million and $110 million , respectively. Outstanding capital lease obligations and the related capital assets are not material to the consolidated balance sheets at March 31, 2016 and 2015 . In connection with the fleet vehicle operating leases, the Company guarantees a residual value of $32 million , representing approximately 9.8% of the original cost of the equipment currently under lease. At March 31, 2016 , future minimum lease payments under non-cancelable operating leases were as follows: (In thousands) Years Ending March 31, 2017 $ 112,059 2018 94,419 2019 72,522 2020 53,725 2021 35,126 Thereafter 44,651 $ 412,502

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES Litigation On May 5, 2016, Airgas Doral, Inc. (“Airgas Doral”), a wholly-owned subsidiary of Airgas, Inc. and the operator of the Doral, Florida fill plant and export business, entered a guilty plea pursuant to a Plea Agreement with the United States Attorney’s Office for the Southern District of Florida. Under the terms of the Plea Agreement, Airgas Doral pled guilty to 14 counts of violating various Department of Transportation regulations in connection with eight international shipments of argon in 2008. After accepting Airgas Doral’s plea, the Court scheduled a sentencing hearing for May 26, 2016, at which time the Court will impose a sentence, including a fine, a term of probation, and possibly an award of restitution. Under the Plea Agreement, the United States Attorney’s Office for the Southern District of Florida and Airgas Doral jointly recommended, among other things, that the Court should impose a fine totaling $7 million , although the Court is not obligated to follow that joint recommendation. The Company has accrued that recommended amount at March 31, 2016. The Company does not believe that the expected resolution of this matter will have a material impact on the Company’s financial position, nor does Airgas Doral expect it to affect any of its business licensing, negotiations, or qualifications to operate under the Department of Transportation, Food and Drug Administration, or other regulatory agency standards. In addition, the Company is involved in various other legal and regulatory proceedings that have arisen in the ordinary course of business and have not been fully adjudicated. These actions, when ultimately concluded and determined, will not, in the opinion of management, have a material adverse effect upon the Company’s consolidated financial condition, results of operations or liquidity. Merger Agreement As described in Note 2, the Company has incurred $29 million of merger-related costs during fiscal 2016, primarily consisting of legal, advisory and other professional fees in connection with the Merger. The Company expects to incur additional costs in the future related to the Merger. Insurance Coverage The Company has established insurance programs to cover workers’ compensation, business automobile and general liability claims. During fiscal 2016 , 2015 and 2014 , these programs had deductible limits of $1 million per occurrence. For fiscal 2017 , the deductible limits are expected to remain at $1 million per occurrence. The Company believes its business insurance reserves are adequate (see Note 9). The Company accrues estimated losses using actuarial models and assumptions based on historical loss experience. The nature of the Company’s business may subject it to product and general liability lawsuits. To the extent that the Company is subject to claims that exceed its liability insurance coverage, such suits could have a material adverse effect on the Company’s financial position, results of operations or liquidity. The Company maintains a self-insured health benefits plan, which provides medical benefits to employees electing coverage under the plan. The Company maintains a reserve for incurred but not reported medical claims and claim development. The reserve is an estimate based on historical experience and other assumptions, some of which are subjective. The Company adjusts its self-insured medical benefits reserve as the Company’s loss experience changes due to medical inflation, changes in the number of plan participants and an aging employee base. The Company’s self-insured medical benefits reserve was $14.0 million and $13.8 million at March 31, 2016 and 2015 , respectively. Supply Agreements The Company purchases bulk quantities of industrial gases under take-or-pay supply agreements. The Company is a party to take-or-pay supply agreements under which Air Products and Chemicals, Inc. (“Air Products”) will supply the Company with bulk nitrogen, oxygen, argon, hydrogen and helium. The Company is committed to purchase a minimum of approximately $61 million in bulk gases within the next fiscal year under the Air Products supply agreements. The agreements expire at various dates through 2020 . The Company also has take-or-pay supply agreements with The Linde Group AG to purchase oxygen, nitrogen, argon and helium. The agreements expire at various dates through 2025 and represent approximately $95 million in minimum bulk gas purchases for the next fiscal year. Additionally, the Company has take-or-pay supply agreements to purchase oxygen, nitrogen, argon, helium and ammonia from other major producers. Minimum purchases under these contracts for the next fiscal year are approximately $36 million and they expire at various dates through 2026 . The Company also purchases liquid carbon dioxide under take-or-pay supply agreements with twelve suppliers that expire at various dates through 2044 and represent minimum purchases of approximately $20 million for the next fiscal year . The level of annual purchase commitments under the Company’s supply agreements beyond the next fiscal year vary based on the expiration of agreements at different dates in the future, among other factors. The Company’s annual purchase commitments under all of its supply agreements reflect estimates based on fiscal 2016 purchases. The Company’s supply agreements contain periodic pricing adjustments, most of which are based on certain economic indices and market analyses. The Company believes the minimum product purchases under the agreements are within the Company’s normal product purchases. Actual purchases in future periods under the supply agreements could differ materially from those presented due to fluctuations in demand requirements related to varying sales levels as well as changes in economic conditions. If a supply agreement with a major supplier of gases or other raw materials was terminated, the Company would attempt to locate alternative sources of supply to meet customer requirements, including utilizing excess internal production capacity for atmospheric gases. The Company purchases hardgoods from major manufacturers and suppliers. For certain products, the Company has negotiated national purchasing arrangements. The Company believes that if an arrangement with any supplier of hardgoods was terminated, it would be able to negotiate comparable alternative supply arrangements. At March 31, 2016 , future commitments under take-or-pay supply agreements were as follows: (In thousands) Years Ending March 31, 2017 $ 212,212 2018 176,650 2019 136,203 2020 92,058 2021 45,613 Thereafter 198,069 $ 860,805 Construction Commitments Construction commitments of approximately $48 million at March 31, 2016 represent outstanding commitments to complete authorized construction projects. At March 31, 2016 , the Company had long-term agreements with two customers to construct on-site air separation units. The units are located in Calvert City, KY and Tuscaloosa, AL. Letters of Credit At March 31, 2016 , the Company had outstanding letters of credit of $51 million . Letters of credit are guarantees of payment to third parties. The Company’s letters of credit principally back obligations associated with the Company’s deductible on workers’ compensation, business automobile and general liability claims. The letters of credit are supported by the Company’s Credit Facility.

Benefit Plans

Benefit Plans	12 Months Ended
	Mar. 31, 2016
General Discussion of Pension and Other Postretirement Benefits [Abstract]
Benefit Plans	BENEFIT PLANS The Company has a defined contribution 401(k) plan (the “401(k) plan”) covering substantially all full-time employees. Under the terms of the 401(k) plan, the Company makes matching contributions of up to two percent of participant wages. Amounts expensed under the 401(k) plan for fiscal 2016 , 2015 and 2014 were $14.0 million , $13.0 million and $12.3 million , respectively. The Company has a deferred compensation plan that is a non-qualified plan. The deferred compensation plan allows eligible employees and non-employee directors, who elect to participate in the plan, to defer the receipt of taxable compensation . Participants may set aside up to a maximum of 75% of their base salary and up to a maximum of 100% of their bonus compensation or directors’ fees in tax-deferred investments. The Company’s deferred compensation plan liabilities are funded through an irrevocable rabbi trust. The assets of the trust, which consist of open-ended mutual funds, cannot be reached by the Company or its creditors except in the event of the Company’s insolvency or bankruptcy. Assets held in the rabbi trust were $17.7 million and $16.3 million at March 31, 2016 and 2015 , respectively, and are included within other non-current assets on the consolidated balance sheets. The Company’s deferred compensation plan liabilities were $17.7 million and $16.3 million at March 31, 2016 and 2015 , respectively, and are included within other non-current liabilities on the consolidated balance sheets. Gains or losses on the deferred compensation plan assets are recognized as other income, net, while gains or losses on the deferred compensation plan liabilities are recognized as compensation expense in the consolidated statements of earnings.

Related Parties

Related Parties	12 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Related Parties	RELATED PARTIES The Company purchases and sells goods and services in the ordinary course of business with certain corporations in which some of its directors and an officer are officers or directors. The Company also leases certain operating facilities from employees and an officer who were previous owners of businesses acquired. Payments made to related parties for fiscal 2016 , 2015 and 2014 were $5.0 million , $4.2 million and $4.1 million , respectively.

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	12 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Information [Abstract]
Supplemental Cash Flow Information	SUPPLEMENTAL CASH FLOW INFORMATION Cash Paid for Interest and Income Taxes Cash paid for interest and income taxes was as follows: Years Ended March 31, (In thousands) 2016 2015 2014 Interest paid $ 64,992 $ 62,986 $ 86,479 Income taxes, net of refunds 170,840 194,161 164,482 Noncash Investing and Financing Activities Liabilities assumed and stock issued as a result of acquisitions were as follows: Years Ended March 31, (In thousands) 2016 2015 2014 Fair value of assets acquired $ 121,348 $ 66,626 $ 218,413 Net cash paid for acquisitions (a) (102,032 ) (51,827 ) (205,370 ) Stock issued for acquisition (b) — (4,458 ) — Liabilities assumed $ 19,316 $ 10,341 $ 13,043 ____________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. (b) Represents shares of Airgas, Inc. common stock issued in connection with a single prior year acquisition.

Summary by Business Segment

Summary by Business Segment	12 Months Ended
	Mar. 31, 2016
Segment Reporting, Measurement Disclosures [Abstract]
Summary by Business Segment	SUMMARY BY BUSINESS SEGMENT The Company identifies its businesses as separate operating segments for reporting purposes based on the review of discrete financial results for each of the businesses by the Company’s chief operating decision maker for performance assessment and resource allocation purposes. The Company aggregates its operating segments, based on products and services, into two business segments, Distribution and All Other Operations. The Distribution business segment represents the Company’s only reportable segment under GAAP, while the All Other Operations business segment represents the aggregation of all other operating segments of the Company not considered reportable under GAAP. The Distribution business segment consists of 21 operating segments, including fourteen regional gas and hardgoods distribution businesses, four gas companies that either produce or market gas products sold primarily through the Company’s regional distribution businesses, two companies that sell or provide safety-related products and services, and the Company’s rental welder business. The aggregation of the operating segments that form the Distribution business segment is based on the segment’s foundation as a national integrated distribution business providing a broad array of gas products and supporting services offered in all modes of gas distribution, from large bulk quantities to smaller quantities in cylinder or packaged form, as well as a broad complementary hardgoods product line. Although there have been minor internal organizational changes in certain operating segments that comprise the Distribution business segment, there were no changes to this reportable segment from the prior year. The Distribution business segment’s principal products include industrial, medical and specialty gases sold in packaged and bulk quantities, as well as hardgoods. The Company’s air separation facilities and national specialty gas labs primarily produce gases that are sold by the regional distribution businesses. Gas sales include nitrogen, oxygen, argon, helium, hydrogen, welding and fuel gases such as acetylene, propylene and propane, carbon dioxide, nitrous oxide, ultra high purity grades, special application blends and process chemicals. Business units in the Distribution business segment also recognize rental revenue, derived from gas cylinders, cryogenic liquid containers, bulk storage tanks, tube trailers and welding and welding related equipment. Gas and rent represented 61% , 59% and 60% of the Distribution business segment’s sales in fiscal years 2016 , 2015 and 2014 , respectively. Hardgoods consist of welding consumables and equipment, safety products, construction supplies, and maintenance, repair and operating supplies. Hardgoods sales represented 39% , 41% and 40% of the Distribution business segment’s sales in fiscal years 2016 , 2015 and 2014 , respectively. The Distribution business segment accounted for approximately 90% of consolidated sales in each of the fiscal years 2016 , 2015 and 2014 . The All Other Operations business segment consists of six business units which primarily manufacture and/or distribute carbon dioxide, dry ice, nitrous oxide, ammonia and refrigerant gases, along with a nitrogen services business .The operating segments reflected in the All Other Operations business segment individually do not meet the thresholds to be reported as separate reportable segments. Elimination entries represent intercompany sales from the Company’s All Other Operations business segment to its Distribution business segment. The Company’s operations are predominantly in the United States. While the Company does conduct operations outside of the United States in Canada, Mexico, Russia, Dubai and several European countries , revenues from foreign countries represent less than 2% of the Company’s net sales . Revenues derived from foreign countries, based on the point of sale, were $88 million , $93 million and $88 million in the fiscal years ended March 31, 2016 , 2015 and 2014 , respectively. Long-lived assets attributable to the Company’s foreign operations represent less than 5% of the consolidated total long-lived assets of the Company and were $137 million , $143 million and $148 million at March 31, 2016 , 2015 and 2014 , respectively. Long-lived assets primarily consist of plant and equipment, net. The Company’s customer base is diverse with its largest customer accounting for less than 1% of total net sales. Business segment information for the Company’s Distribution and All Other Operations business segments is presented in the following tables for the years ended March 31, 2016 , 2015 and 2014 . The accounting policies of the business segments are the same as those described in the Summary of Significant Accounting Policies (Note 1). Although corporate operating expenses are generally allocated to each business segment based on sales dollars, the Company reported expenses related to the Air Liquide merger under selling, distribution and administrative expenses in the “Eliminations and Other” column. Additionally, the Company’s other special charges are not allocated to the Company’s business segments, and are also reflected in the “Eliminations and Other” column. Corporate assets have been allocated to the Distribution business segment, intercompany sales are recorded on the same basis as sales to third parties, and intercompany transactions are eliminated in consolidation. See Note 4 for the impact of acquisitions on the operating results of each business segment. Management utilizes more than one measurement and multiple views of data to measure segment performance and to allocate resources to the segments. However, the predominant measurements are consistent with the Company’s consolidated financial statements and, accordingly, are reported on the same basis in the following tables. Year Ended March 31, 2016 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,866,065 $ 631,646 $ (38,209 ) $ 3,459,502 Hardgoods 1,850,163 4,123 (11 ) 1,854,275 Net sales (a) 4,716,228 635,769 (38,220 ) 5,313,777 Cost of products sold (excluding depreciation) (a) 2,037,492 302,326 (38,220 ) 2,301,598 Selling, distribution and administrative expenses 1,828,814 213,940 — 2,042,754 Merger costs and other special charges — — 35,967 35,967 Depreciation 288,704 29,848 — 318,552 Amortization 29,403 4,792 — 34,195 Total costs and expenses 4,184,413 550,906 (2,253 ) 4,733,066 Operating income $ 531,815 $ 84,863 $ (35,967 ) $ 580,711 Assets $ 5,531,042 $ 603,914 $ — $ 6,134,956 Capital expenditures $ 426,290 $ 30,609 $ — $ 456,899 Year Ended March 31, 2015 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,823,297 $ 556,941 $ (29,219 ) $ 3,351,019 Hardgoods 1,950,192 3,681 (7 ) 1,953,866 Net sales (a) 4,773,489 560,622 (29,226 ) 5,304,885 Cost of products sold (excluding depreciation) (a) 2,092,466 292,635 (29,226 ) 2,355,875 Selling, distribution and administrative expenses 1,792,116 186,558 — 1,978,674 Depreciation 272,200 25,510 — 297,710 Amortization 27,373 3,975 — 31,348 Total costs and expenses 4,184,155 508,678 (29,226 ) 4,663,607 Operating income $ 589,334 $ 51,944 $ — $ 641,278 Assets $ 5,397,535 $ 576,075 $ — $ 5,973,610 Capital expenditures $ 438,867 $ 29,922 $ — $ 468,789 Year Ended March 31, 2014 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,717,272 $ 539,954 $ (30,404 ) $ 3,226,822 Hardgoods 1,841,518 4,200 (3 ) 1,845,715 Net sales (a) 4,558,790 544,154 (30,407 ) 5,072,537 Cost of products sold (excluding depreciation) (a) 1,996,065 281,916 (30,407 ) 2,247,574 Selling, distribution and administrative expenses 1,705,408 176,289 7,426 1,889,123 Depreciation 252,329 23,132 — 275,461 Amortization 25,512 4,333 — 29,845 Total costs and expenses 3,979,314 485,670 (22,981 ) 4,442,003 Operating income $ 579,476 $ 58,484 $ (7,426 ) $ 630,534 Assets $ 5,222,781 $ 570,533 $ — $ 5,793,314 Capital expenditures $ 317,066 $ 37,521 $ — $ 354,587 ____________________ (a) Amounts in the “Eliminations and Other” column represent the elimination of intercompany sales and associated gross profit on sales from the Company’s All Other Operations business segment to its Distribution business segment.

Supplementary Information (Unau

Supplementary Information (Unaudited)	12 Months Ended
	Mar. 31, 2016
Selected Quarterly Financial Information [Abstract]
Supplementary Information (Unaudited)	SUPPLEMENTARY INFORMATION (UNAUDITED) The following table summarizes the unaudited results of operations for each quarter of fiscal 2016 and 2015 : (In thousands, except per share amounts) First Second Third Fourth 2016 Net sales $ 1,349,710 $ 1,374,569 $ 1,295,414 $ 1,294,084 Operating income (b) 152,578 170,145 125,587 132,401 Net earnings 88,235 98,034 73,864 77,367 Basic earnings per share (a) $ 1.17 $ 1.33 $ 1.02 $ 1.07 Diluted earnings per share (a) $ 1.16 $ 1.31 $ 1.01 $ 1.05 2015 Net sales $ 1,313,587 $ 1,357,755 $ 1,331,820 $ 1,301,723 Operating income 155,081 175,781 162,886 147,530 Net earnings 88,852 98,312 93,199 87,723 Basic earnings per share (a) $ 1.20 $ 1.32 $ 1.25 $ 1.17 Diluted earnings per share (a) $ 1.18 $ 1.30 $ 1.23 $ 1.15 ____________________ (a) Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding in each quarter. Therefore, the sum of the quarterly earnings per share does not necessarily equal the full year earnings per share disclosed on the consolidated statements of earnings. (b) Operating income includes the following items: (In thousands) First Second Third Fourth 2016 Merger costs (Note 2) $ — $ — $ 21,393 $ 7,574 Special charges (Note 18) — — — 7,000

Subsequent Events

Subsequent Events	12 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS On April 15, 2016, the Company announced it has elected to redeem all $250 million of its outstanding 2.95% Notes maturing in June 2016 (“2016 Notes”). The notes will be redeemed in full on May 15, 2016, at a price of 100% . On April 26, 2016, the Company announced the commencement of a consent solicitation, at the request and expense of Air Liquide, relating to all of its outstanding senior notes, excluding its 2016 Notes which the Company has elected to redeem on May 15, 2016, (“Affected Notes”) in connection with the previously announced merger with Air Liquide (see Note 2). The Company solicited the consents of holders of Affected Notes to amend the indenture dated as of May 27, 2010 between the Company and U.S. Bank National Association, as trustee, as amended and supplemented from time to time (the "Indenture"), to modify the reporting covenants with respect to the Affected Notes so that, following the closing of the Merger, in the event that (and for so long as) Air Liquide provides an unconditional guarantee of the Company's payment obligations under the Indenture and the Affected Notes, Air Liquide will provide its periodic and current reporting (under applicable French law) in lieu of the Company's existing periodic and current reporting obligations. Air Liquide has no obligation to guarantee the Affected Notes, and there can be no assurance that Air Liquide will do so. On May 10, 2016 the Company announced that holders of a majority in aggregate principal amount of Affected Notes have delivered valid consents in connection with the Company’s proposed amendments (the “Amendments”) to the Indenture. The terms and conditions of the Amendments are set forth in the consent solicitation statement dated April 26, 2016, as supplemented by a supplement dated May 2, 2016 (together, the “Statement”). The Company will, subject to the satisfaction or waiver of certain conditions described in the Statement, including the closing of the Merger, promptly pay to each holder of Affected Notes who delivered (and did not revoke) a valid consent in favor of the Amendments prior to 5:00 p.m., New York City time, on May 9, 2016, a cash payment of $1.50 for each $1,000 principal amount of Affected Notes in respect of which such holder delivered (and did not revoke) a valid consent.

Valuation and Qualifying Accoun

Valuation and Qualifying Accounts	12 Months Ended
	Mar. 31, 2016
Valuation and Qualifying Accounts [Abstract]
Valuation and Qualifying Accounts	SCHEDULE II AIRGAS, INC. AND SUBSIDIARIES Valuation and Qualifying Accounts for the Years Ended March 31, 2016 , 2015 and 2014 (In thousands) Additions Description Balance at Beginning of Period Charged to Costs and Expenses Charged to Other Accounts (a) Deductions (b) Balance at End of Period 2016 Accounts receivable - allowances for doubtful accounts $ 27,016 $ 16,680 $ 4,349 $ (21,086 ) $ 26,959 2015 Accounts receivable - allowances for doubtful accounts $ 31,757 $ 15,843 $ 3,228 $ (23,812 ) $ 27,016 2014 Accounts receivable - allowances for doubtful accounts $ 28,650 $ 20,310 $ 7,163 $ (24,366 ) $ 31,757 ____________________ (a) Principally reflects subsequent collections of accounts previously written-off. (b) Write-off of uncollectible accounts.

Summary of Significant Accoun34

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Basis of Presentation	The consolidated financial statements include the accounts of Airgas, Inc. and its subsidiaries. Intercompany accounts and transactions are eliminated in consolidation. The Company has made estimates and assumptions relating to the reporting of assets and liabilities and disclosure of contingent assets and liabilities to prepare these consolidated financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”). Estimates are used for, but not limited to, determining the net carrying value of trade receivables, inventories, plant and equipment, goodwill, other intangible assets, asset retirement obligations, business and health insurance reserves, loss contingencies and deferred tax assets. Actual results could differ from those estimates.
Cash and Cash Overdraft	On a daily basis, available funds are swept from depository accounts into a concentration account and used to repay borrowings under the Company’s commercial paper program. Cash principally represents the balance of customer checks that have not yet cleared through the banking system and become available to be swept into the concentration account, and deposits made subsequent to the daily cash sweep. The Company does not fund its disbursement accounts for checks it has written until the checks are presented to the bank for payment. Cash overdrafts represent the balance of outstanding checks and are classified with other current liabilities. There are no compensating balance requirements or other restrictions on the transfer of cash associated with the Company’s depository accounts.
Allowance for Doubtful Accounts	The Company maintains an allowance for doubtful accounts, which includes sales returns, sales allowances and bad debts. The allowance adjusts the carrying value of trade receivables for the estimate of accounts that will ultimately not be collected. An allowance for doubtful accounts is generally established as trade receivables age beyond their due dates, whether as bad debts or as sales returns and allowances. As past due balances age, higher valuation allowances are established, thereby lowering the net carrying value of receivables. The amount of valuation allowance established for each past-due period reflects the Company’s historical collections experience, including that related to sales returns and allowances, as well as current economic conditions and trends. The Company also qualitatively establishes valuation allowances for specific problem accounts and bankruptcies, and other accounts that the Company deems relevant for specifically identified allowances. The amounts ultimately collected on past due trade receivables are subject to numerous factors including general economic conditions, the condition of the receivable portfolios assumed in acquisitions, the financial condition of individual customers and the terms of reorganization for accounts exiting bankruptcy. Changes in these conditions impact the Company’s collection experience and may result in the recognition of higher or lower valuation allowances.
Inventories	Inventories are stated at the lower of cost or net realizable value. Cost is determined using the first-in, first-out (“FIFO”) and average-cost methods. Substantially all of the inventories are finished goods.
Plant and Equipment	Plant and equipment are initially stated at cost. Long-lived assets, including plant and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the recorded values cannot be recovered from the undiscounted future cash flows. For impairment testing purposes, long-lived assets are grouped with other assets and liabilities at the lowest level for which independent identifiable cash flows are determinable. When the book value of an asset or group of assets exceeds the associated undiscounted expected future cash flows, it is considered to be potentially impaired and is written down to fair value, which is determined based on either discounted future cash flows or appraised values. The Company also leases property, plant and equipment, principally under operating leases. Rent expense for operating leases, which may have escalating rentals or rent holidays, is recorded on a straight-line basis over the respective lease terms. The Company determines depreciation expense using the straight-line method based on the estimated useful lives of the related assets. The Company uses accelerated depreciation methods for tax purposes where appropriate. Depreciation expense is recognized on the Company’s plant and equipment in the consolidated statement of earnings line item “Depreciation.” The Company capitalizes the interest cost associated with the development and construction of significant new plant and equipment and depreciates that amount over the lives of the related assets. Capitalized interest recorded for construction in progress during each of the years in the three-year period ended March 31, 2016 was not material.
Computer Software	The Company capitalizes certain costs incurred to purchase or develop computer software for internal use. These costs include purchased software packages, payments to vendors and consultants for the development, implementation or modification of purchased software packages for Company use, payroll and related costs for employees associated with internal-use software projects, interest costs incurred in developing software for internal use, and software costs that allow for access or conversion of old data by new internal-use software. Capitalized computer software costs are included within plant and equipment on the Company’s consolidated balance sheets and depreciated over the estimated useful life of the computer software, which is generally three to ten years.
Goodwill and Intangible Assets	Goodwill is an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. The Company is required to test goodwill associated with each of its reporting units for impairment at least annually and whenever events or circumstances indicate that it is more likely than not that goodwill may be impaired. The Company performs its annual goodwill impairment test as of October 31 of each year. Other intangible assets primarily consist of non-competition agreements and customer relationships resulting from business acquisitions. Both non-competition agreements and customer relationships are recorded based on their acquisition date fair values. Non-competition agreements are amortized using the straight-line method over the respective terms of the agreements. Customer relationships are amortized using the straight-line method over their estimated useful lives, which range from seven to 25 years. The determination of the estimated benefit periods associated with customer relationships is based on an analysis of historical customer sales attrition information and other customer-related factors at the date of acquisition. There are no expected residual values related to the Company’s other intangible assets. The Company evaluates the estimated benefit periods and recoverability of its other intangible assets when facts and circumstances indicate that the lives may not be appropriate and/or the carrying values of the asset group containing other intangible assets may not be recoverable through the projected undiscounted future cash flows of the group. If the carrying value of the asset group containing other intangible assets is not recoverable, impairment is measured as the amount by which the carrying value exceeds its estimated fair value. Fair value is determined using discounted cash flows or other techniques.
Deferred Financing Costs	Financing costs related to the issuance of long-term debt are deferred and included in prepaid expenses and other current assets or in other non-current assets, depending upon the classification of the debt to which the costs relate. Deferred financing costs are amortized as interest expense over the term of the related debt instrument.
Asset Retirement Obligations	The fair value of a liability for an asset retirement obligation is recognized in the period during which the asset is placed in service. The fair value of the liability is estimated using projected discounted cash flows. In subsequent periods, the retirement obligation is accreted to its future value, which is the estimate of the obligation at the asset retirement date. When the asset is placed in service, a corresponding retirement asset equal to the fair value of the retirement obligation is also recorded as part of the carrying amount of the related long-lived asset and depreciated over the asset’s useful life. The majority of the Company’s asset retirement obligations are related to the restoration costs associated with returning plant and bulk tank sites to their original condition upon termination of long-term leases or supply agreements. The Company’s asset retirement obligations totaled $22.8 million and $20.4 million at March 31, 2016 and 2015 , respectively, and are reflected within other non-current liabilities on the Company’s consolidated balance sheets.
Loss Contingencies	Liabilities for loss contingencies arising from claims, assessments, litigation and other sources are recorded when it is probable that a liability has been incurred and the amount of the claim, assessment or damages can be reasonably estimated. The Company maintains business insurance programs with deductible limits, which cover workers’ compensation, business automobile and general liability claims. The Company accrues estimated losses using actuarial models and assumptions based on historical loss experience. The actuarial calculations used to estimate business insurance reserves are based on numerous assumptions, some of which are subjective. The Company will adjust its business insurance reserves, if necessary, in the event future loss experience differs from historical loss patterns.
Income Taxes	Income taxes are accounted for under the asset and liability method. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of assets and liabilities and their respective tax bases, and operating loss carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences and operating loss carryforwards are expected to be recovered, settled or utilized. 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. Valuation allowances are recorded to reduce deferred tax assets when it is more likely than not that a tax benefit will not be realized. The Company recognizes the benefit of an income tax position only if it is more likely than not (greater than 50%) that the tax position will be sustained upon tax examination, based solely on the technical merits of the tax position. Otherwise, no benefit is recognized. The tax benefits recognized are measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. Additionally, the Company accrues interest and related penalties, if applicable, on all tax exposures for which reserves have been established consistent with jurisdictional tax laws. Interest and penalties are classified as income tax expense in the consolidated statements of earnings.
Foreign Currency Translation	The functional currency of the Company’s foreign operations is the applicable local currency. The translation of foreign currencies into U.S. dollars is performed for balance sheet accounts using current exchange rates in effect at the balance sheet date and for revenue and expense accounts using average exchange rates during each reporting period. The gains or losses resulting from such translations are included in stockholders’ equity as a component of accumulated other comprehensive loss. Gains and losses arising from foreign currency transactions are reflected in the consolidated statements of earnings as incurred.
Treasury Stock	The Company records repurchases of its common stock for treasury at cost. Upon the reissuance of the Company’s common stock from treasury, differences between the proceeds from reissuance and the average cost of the treasury stock are credited or charged to capital in excess of par value to the extent of prior credits related to the reissuance of treasury stock. If no such credits exist, the differences are charged to retained earnings.
Concentrations of Credit Risk	Financial instruments that potentially subject the Company to concentrations of credit risk consist principally of trade receivables. Concentrations of credit risk are limited due to the Company’s large number of customers and their dispersion across many industries primarily throughout North America. Credit terms granted to customers are generally net 30 days.
Derivative Instruments and Hedging Activities	The Company’s involvement with derivative instruments has been limited to interest rate swap and treasury rate lock agreements used to manage well-defined interest rate risk exposures. An interest rate swap is a contractual exchange of interest payments between two parties. A standard interest rate swap involves the payment of a fixed rate times a notional amount by one party in exchange for receiving a floating rate times the same notional amount from the other party. As interest rates change, the difference to be paid or received is accrued and recognized as interest expense or income over the life of the agreement. Treasury rate lock agreements are used to fix the interest rate related to forecasted debt issuances. Interest rate swap and treasury rate lock agreements are not entered into for trading purposes. When the Company has derivative instruments outstanding, it monitors its positions as well as the credit ratings of its counterparties, including the potential for non-performance by the counterparties. The Company recognizes outstanding derivative instruments as either assets or liabilities at fair value on the consolidated balance sheet. Interest rate contracts have traditionally been designated as hedges and recorded at fair value, with changes in fair value recognized in either accumulated other comprehensive income or in the carrying value of the hedged portions of fixed-rate debt, as applicable. Gains and losses on derivative instruments representing hedge ineffectiveness were recognized immediately in the respective year’s earnings.
Revenue Recognition	Revenue from sales of gases and hardgoods products is recognized when the product is shipped, the sales price is fixed or determinable and collectability is reasonably assured. Rental fees on cylinders, cryogenic liquid containers, bulk gas storage tanks and other equipment are recognized when earned. For contracts that contain multiple deliverables, principally product supply agreements for gases and container rental, revenue is recognized for each deliverable as a separate unit of accounting, with selling prices derived from Company specific or third-party evidence. For cylinder lease agreements in which rental fees are collected in advance, revenues are deferred and recognized over the respective terms of the lease agreements. Amounts billed for sales tax, value added tax or other transactional taxes imposed on revenue-producing transactions are presented on a net basis and are not recognized as revenue.
Cost of Products Sold (Excluding Depreciation)	Cost of products sold (excluding depreciation) for the Distribution business segment includes the cost of direct materials, freight-in and maintenance costs associated with cylinders, cryogenic liquid containers and bulk tanks. Cost of products sold (excluding depreciation) related to gases produced by the Company’s air separation facilities includes direct manufacturing expenses, such as direct labor, power and overhead. Cost of products sold (excluding depreciation) for the All Other Operations business segment principally consists of direct material costs, freight-in and direct manufacturing expenses, such as direct labor, power and overhead.
Selling, Distribution and Administrative Expenses	Selling, distribution and administrative expenses consist of labor and overhead associated with the purchasing, marketing and distribution of the Company’s products, as well as costs associated with a variety of administrative functions such as legal, treasury, accounting and tax, and facility-related expenses.
Shipping and Handling Fees and Distribution Costs	The Company recognizes delivery and freight charges to customers as elements of net sales. Costs of third-party freight-in are recognized as cost of products sold (excluding depreciation). The majority of the costs associated with the distribution of the Company’s products, which include labor and overhead associated with filling, warehousing and delivery by Company and third-party vehicles, are reflected in selling, distribution and administrative expenses and were $918 million , $889 million and $850 million for the fiscal years ended March 31, 2016 , 2015 and 2014 , respectively. The Company conducts multiple operations out of the same facilities and does not allocate facility-related expenses to each operational function. Accordingly, there is no facility-related expense in the distribution costs disclosed above. Depreciation expense associated with the Company’s delivery fleet of $33 million , $32 million and $32 million was recognized in depreciation for the fiscal years ended March 31, 2016 , 2015 and 2014 , respectively.
Stock-based Compensation	The Company grants stock-based compensation awards in connection with its equity incentive and employee stock purchase plans. Stock-based compensation expense is generally recognized on a straight-line basis over the stated vesting period for each award, with accelerated vesting for retirement-eligible employees in accordance with the provisions of the equity incentive plan. See Note 14 for additional disclosures relating to stock-based compensation.
Business Combinations	Acquisitions are recorded using the acquisition method of accounting and accordingly, results of their operations are included in the Company’s consolidated financial statements from the effective date of each respective acquisition. The Company negotiates the respective purchase prices of acquired businesses based on the expected cash flows to be derived from their operations after integration into the Company’s existing distribution, production and service networks. The acquisition purchase price for each business is allocated based on the fair values of the assets acquired and liabilities assumed. Management estimates the fair values of acquired intangible assets other than goodwill using the income approach (i.e. discounted cash flows), and plant and equipment using either the cost or market approach, depending on the type of fixed asset.
Earnings Per Share	Basic earnings per share is calculated by dividing net earnings by the weighted average number of shares of the Company’s common stock outstanding during the period. Outstanding shares consist of issued shares less treasury stock. Diluted earnings per share is calculated by dividing net earnings by the weighted average common shares outstanding adjusted for the dilutive effect of common stock equivalents related to stock options and the Company’s ESPP. Outstanding stock options that are anti-dilutive are excluded from the Company’s diluted earnings per share computation.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Mar. 31, 2016
Business Combinations [Abstract]
Summary of the Consideration Transferred and the Fair Values of the Assets Acquired and Liabilities Assumed [Table Text Block]	The following table summarizes, as of March 31, 2014 , the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2014 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 204,957 $ 413 $ 205,370 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 14,631 $ 9 $ 14,640 Plant and equipment 48,919 (746 ) 48,173 Other intangible assets 60,190 — 60,190 Current liabilities (6,088 ) 1,366 (4,722 ) Non-current liabilities (8,321 ) — (8,321 ) Total identifiable net assets 109,331 629 109,960 Goodwill 95,626 (216 ) 95,410 $ 204,957 $ 413 $ 205,370 ________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. The following table summarizes, as of March 31, 2015 , the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2015 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 50,774 $ 1,053 $ 51,827 Airgas, Inc. common stock (b) 4,458 — 4,458 Fair value of total consideration transferred $ 55,232 $ 1,053 $ 56,285 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 9,705 $ 3 $ 9,708 Plant and equipment 13,824 — 13,824 Other intangible assets 15,122 1,040 16,162 Current liabilities (5,765 ) (50 ) (5,815 ) Non-current liabilities (4,526 ) — (4,526 ) Total identifiable net assets 28,360 993 29,353 Goodwill 26,872 60 26,932 $ 55,232 $ 1,053 $ 56,285 __________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. (b) Represents 41,060 shares of Airgas, Inc. common stock issued in connection with a single acquisition. The fair value of the shares issued as part of the consideration for the acquisition was determined based on the closing sales price of Airgas, Inc. common stock on the acquisition date. The following table summarizes the consideration transferred and the estimated fair values of the assets acquired and liabilities assumed for fiscal 2016 acquisitions, as well as adjustments to finalize the valuations of certain prior year acquisitions. Valuation adjustments related to prior year acquisitions were not significant. (In thousands) Distribution All Other Total Consideration Cash (a) $ 58,018 $ 44,014 $ 102,032 Recognized amounts of identifiable assets acquired and liabilities assumed Current assets, net $ 8,532 $ 2,228 $ 10,760 Plant and equipment 11,701 13,246 24,947 Other intangible assets 24,057 12,769 36,826 Current liabilities (7,216 ) (4,247 ) (11,463 ) Non-current liabilities (3,856 ) (3,997 ) (7,853 ) Total identifiable net assets 33,218 19,999 53,217 Goodwill 24,800 24,015 48,815 $ 58,018 $ 44,014 $ 102,032 ____________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions.
Pro Forma Operating Results	The following table provides unaudited pro forma results of operations for fiscal 2015 and 2014 , as if fiscal 2015 acquisitions had occurred on April 1, 2013 . The pro forma operating results were prepared for comparative purposes only and do not purport to be indicative of what would have occurred had the acquisitions been made as of April 1, 2013 or of results that may occur in the future. Unaudited Years Ended March 31, (In thousands, except per share amounts) 2015 2014 Net sales $ 5,327,458 $ 5,123,949 Net earnings 368,305 351,941 Diluted earnings per share $ 4.86 $ 4.70 The following table provides unaudited pro forma results of operations for fiscal 2016 and 2015 , as if fiscal 2016 acquisitions had occurred on April 1, 2014 . The pro forma results were prepared from financial information obtained from the sellers of the businesses, as well as information obtained during the due diligence process associated with the acquisitions. The unaudited pro forma results reflect certain adjustments related to the acquisitions, such as increased depreciation and amortization expense resulting from the stepped-up basis to fair value of assets acquired and adjustments to reflect the Company’s borrowing and tax rates. The pro forma operating results do not include any anticipated synergies related to combining the businesses. Accordingly, such pro forma operating results were prepared for comparative purposes only and do not purport to be indicative of what would have occurred had the acquisitions been made as of April 1, 2014 or of results that may occur in the future. Unaudited Years Ended March 31, (In thousands, except per share amounts) 2016 2015 Net sales $ 5,335,812 $ 5,388,313 Net earnings 338,408 372,975 Diluted earnings per share $ 4.55 $ 4.92

Inventories, Net (Tables)

Inventories, Net (Tables)	12 Months Ended
	Mar. 31, 2016
Inventory, Net [Abstract]
Schedule of Inventories, Net	Inventories, net, consist of: (In thousands) March 31, 2016 March 31, 2015 Hardgoods $ 309,897 $ 311,453 Gases 149,624 162,617 $ 459,521 $ 474,070

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of Earnings Before Income Taxes, Domestic and Foreign	Earnings before income taxes were derived from the following sources: Years Ended March 31, (In thousands) 2016 2015 2014 United States $ 527,100 $ 572,182 $ 539,063 Foreign 2,617 11,939 12,842 $ 529,717 $ 584,121 $ 551,905
Schedule of Components of Income Tax Expense	Income tax expense consists of: Years Ended March 31, (In thousands) 2016 2015 2014 Current: Federal $ 148,585 $ 163,774 $ 184,308 Foreign 1,029 2,010 4,561 State 15,413 17,410 19,121 165,027 183,194 207,990 Deferred: Federal 30,792 24,499 (4,722 ) Foreign (197 ) 2,604 (1,127 ) State (3,405 ) 5,738 (1,020 ) 27,190 32,841 (6,869 ) $ 192,217 $ 216,035 $ 201,121
Effective Income Tax Rate Reconciliation	Significant differences between taxes computed at the federal statutory rate and the provision for income taxes were: Years Ended March 31, 2016 2015 2014 Taxes at U.S. federal statutory rate 35.0 % 35.0 % 35.0 % Increase (decrease) in income taxes resulting from: State income taxes, net of federal benefit 1.5 % 2.6 % 2.1 % Domestic production activities deduction (1.2 )% (1.0 )% (1.0 )% Other, net 1.0 % 0.4 % 0.3 % 36.3 % 37.0 % 36.4 %
Schedule of Deferred Tax Assets and Liabilities	The tax effects of cumulative temporary differences and carryforwards that gave rise to the significant portions of the deferred tax assets and liabilities were as follows: March 31, (In thousands) 2016 2015 Deferred Tax Assets: Inventories $ 25,936 $ 27,697 Deferred rental income 17,670 17,986 Insurance reserves 12,410 14,157 Litigation settlement and other reserves 2,330 3,132 Asset retirement obligations 8,279 7,553 Stock-based compensation 36,357 33,538 Other 35,787 19,876 Net operating loss carryforwards 11,070 12,061 Valuation allowance (1,141 ) (671 ) 148,698 135,329 Deferred Tax Liabilities: Plant and equipment (732,503 ) (711,840 ) Intangible assets (227,809 ) (207,690 ) Other (12,822 ) (12,301 ) (973,134 ) (931,831 ) Net deferred tax liability $ (824,436 ) $ (796,502 )
Schedule of Deferred Tax Assets and Liabilities by Balance Sheet Grouping	Current deferred tax assets and current deferred tax liabilities have been netted for presentation purposes. Non-current deferred tax assets and non-current deferred tax liabilities have also been netted. Deferred tax assets and liabilities are reflected in the Company’s consolidated balance sheets as follows: March 31, (In thousands) 2016 2015 Current deferred income tax asset, net $ 69,908 $ 58,072 Non-current deferred income tax liability, net (894,344 ) (854,574 ) Net deferred tax liability $ (824,436 ) $ (796,502 )
Unrecognized Net Income Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized net income tax benefits, including penalties associated with uncertain tax positions, is as follows: March 31, (In thousands) 2016 2015 Beginning unrecognized net income tax benefits $ 20,983 $ 18,224 Additions for current year tax positions 3,845 3,565 Additions for tax positions of prior years 187 1,288 Reductions for tax positions of prior years (3,306 ) (1,646 ) Reductions for settlements with taxing authorities — (234 ) Reductions as a result of expiration of applicable statutes of limitations (787 ) (214 ) Ending unrecognized net income tax benefits $ 20,922 $ 20,983

Plant and Equipment (Tables)

Plant and Equipment (Tables)	12 Months Ended
	Mar. 31, 2016
Property, Plant and Equipment [Abstract]
Plant and Equipment	The major classes of plant and equipment, at cost, are as follows: March 31, Depreciable Lives (Yrs) 2016 2015 (In thousands) Land and land improvements — $ 246,820 $ 225,721 Buildings and improvements 25 634,816 581,076 Cylinders 30 1,504,566 1,461,600 Bulk tank stations 10 to 30 (Average 17) 846,344 789,881 Rental equipment 2 to 10 496,383 466,833 Machinery and equipment 7 to 10 1,057,142 988,857 Computers, furniture and fixtures 3 to 10 296,408 338,316 Transportation equipment 3 to 15 366,221 369,034 Construction in progress — 110,341 83,741 $ 5,559,041 $ 5,305,059

Goodwill and Other Intangible39

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Mar. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Changes In Goodwill by Business Segment	Changes in the carrying amount of goodwill by business segment for fiscal 2016 and 2015 were as follows: (In thousands) Distribution Business Segment All Other Operations Business Segment Total Balance at March 31, 2014 $ 1,092,728 $ 197,168 $ 1,289,896 Acquisitions (a) 26,872 60 26,932 Other adjustments, including foreign currency translation (3,031 ) (153 ) (3,184 ) Balance at March 31, 2015 1,116,569 197,075 1,313,644 Acquisitions (a) 24,800 24,015 48,815 Other adjustments, including foreign currency translation 2,337 (26 ) 2,311 Balance at March 31, 2016 $ 1,143,706 $ 221,064 $ 1,364,770 ____________________ (a) Includes acquisitions completed during the respective year and adjustments made to prior year acquisitions.
Schedule of Other Intangible Assets by Major Class	Other intangible assets by major class are as follows: March 31, 2016 March 31, 2015 (In thousands) Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted Average Amortization Period (Years) Gross Carrying Amount Accumulated Amortization Net Carrying Amount Customer relationships 17 $ 368,096 $ (138,467 ) $ 229,629 17 $ 345,805 $ (120,321 ) $ 225,484 Non-competition agreements 6 45,171 (26,776 ) 18,395 6 43,204 (24,335 ) 18,869 Other 200 (52 ) 148 200 (34 ) 166 $ 413,467 $ (165,295 ) $ 248,172 $ 389,209 $ (144,690 ) $ 244,519

Accrued Expenses and Other Cu40

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Mar. 31, 2016
Accrued Liabilities and Other Liabilities [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities include: (In thousands) March 31, 2016 March 31, 2015 Accrued payroll and employee benefits $ 81,107 $ 98,547 Business insurance reserves (a) 48,176 49,934 Taxes other than income taxes 22,160 22,863 Cash overdraft 72,282 71,537 Deferred rental revenue 34,440 34,538 Accrued interest 10,855 12,860 Other accrued expenses and current liabilities 79,668 56,600 $ 348,688 $ 346,879 ____________________ (a) With respect to the business insurance reserves above, the Company had corresponding insurance receivables of $9.9 million at March 31, 2016 and $11.6 million at March 31, 2015 , which are included within the “Prepaid expenses and other current assets” line item on the Company’s consolidated balance sheets. The insurance receivables represent the balance of probable claim losses in excess of the Company’s deductible for which the Company is fully insured.

Indebtedness (Tables)

Indebtedness (Tables)	12 Months Ended
	Mar. 31, 2016
Debt Instruments [Abstract]
Schedule Of Debt	Total debt consists of: (In thousands) March 31, 2016 March 31, 2015 Short-term Money market loans $ — $ — Commercial paper 383,258 325,871 Short-term debt $ 383,258 $ 325,871 Long-term Trade receivables securitization $ 330,000 $ 295,000 Revolving credit borrowings - U.S. — — Revolving credit borrowings - Multi-currency 70,259 48,332 Revolving credit borrowings - France 6,088 6,277 Senior notes, net 1,798,282 1,648,608 Other long-term debt 298 555 Total long-term debt 2,204,927 1,998,772 Less current portion of long-term debt (250,107 ) (250,110 ) Long-term debt, excluding current portion $ 1,954,820 $ 1,748,662 Total debt $ 2,588,185 $ 2,324,643
Schedule of Senior Notes	The Company’s senior notes consisted of the following: (In thousands) Principal Description Coupon Yield Maturity Date Semi-annual Interest Payment Dates March 31, 2016 March 31, 2015 2015 Notes (a) 3.25% 3.283% 10/01/2015 April 1 and October 1 $ — $ 250,000 2016 Notes (c) 2.95% 2.980% 06/15/2016 June 15 and December 15 250,000 250,000 2018 Notes 1.65% 1.685% 02/15/2018 February 15 and August 15 325,000 325,000 2020 A Notes 2.375% 2.392% 02/15/2020 February 15 and August 15 275,000 275,000 2020 B Notes (b) 3.05% 3.092% 08/01/2020 February 1 and August 1 400,000 — 2022 Notes 2.90% 2.913% 11/15/2022 May 15 and November 15 250,000 250,000 2024 Notes 3.65% 3.673% 07/15/2024 January 15 and July 15 300,000 300,000 1,800,000 1,650,000 Less: unamortized discount (1,718 ) (1,392 ) Senior notes, net $ 1,798,282 $ 1,648,608 ____________________ (a) On September 14, 2015, the Company redeemed in full its 2015 Notes senior notes originally due to mature on October 1, 2015. (b) On August 11, 2015, the Company issued the 2020 B Notes. The net proceeds from the sale of the 2020 Notes were used for general corporate purposes, including to fund acquisitions, to repay indebtedness and to repurchase shares pursuant to the Company’s stock repurchase program. Interest payments on the 2020 Notes commenced on February 1, 2016. (c) The 2016 Notes are included within the “Current portion of long-term debt” line item on the Company’s consolidated balance sheet based on the maturity date.
Schedule of Maturities of Long-term Debt	The aggregate maturities of long-term debt at March 31, 2016 are as follows: (In thousands) Debt Maturities (a) Years Ending March 31, 2017 $ 250,118 2018 325,175 2019 330,004 2020 351,348 2021 400,000 Thereafter 550,000 $ 2,206,645 ____________________ (a) Outstanding borrowings under the Securitization Agreement at March 31, 2016 are reflected as maturing at the agreement’s expiration in December 2018 . The Senior Notes are reflected in the debt maturity schedule at their maturity values rather than their carrying values, which are net of aggregate discounts of $1.7 million at March 31, 2016 .

Derivative Instruments and He42

Derivative Instruments and Hedging Activities (Tables)	12 Months Ended
	Mar. 31, 2016
General Discussion of Derivative Instruments and Hedging Activities [Abstract]
Effect Of Derivative Instruments On Earnings	Location of Gain (Loss) Recognized in Pre-tax Income Amount of Gain (Loss) Recognized in Pre-Tax Income (In thousands) Year Ended March 31, 2014 Derivatives in Fair Value Hedging Relationships Change in fair value of variable interest rate swaps Interest expense, net $ (2,490 ) Change in carrying value of 2013 Notes Interest expense, net 2,496 Net effect Interest expense, net $ 6

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	Assets and liabilities measured at fair value on a recurring basis at March 31, 2016 and 2015 are categorized in the tables below based on the lowest level of significant input to the valuation. During the periods presented, there were no transfers between fair value hierarchical levels. Balance at Quoted prices in active markets Level 1 Significant other observable inputs Level 2 Significant unobservable inputs Level 3 (In thousands) March 31, 2016 Assets: Deferred compensation plan assets $ 17,731 $ 17,731 $ — $ — Liabilities: Deferred compensation plan liabilities $ 17,731 $ 17,731 $ — $ — Balance at Quoted prices in active markets Level 1 Significant other observable inputs Level 2 Significant unobservable inputs Level 3 (In thousands) March 31, 2015 Assets: Deferred compensation plan assets $ 16,288 $ 16,288 $ — $ — Liabilities: Deferred compensation plan liabilities $ 16,288 $ 16,288 $ — $ —
Schedule of Carrying Values and Estimated Fair Values of Debt Instruments	The carrying value of debt, which is reported on the Company’s consolidated balance sheets, generally reflects the cash proceeds received upon its issuance, net of subsequent repayments, plus the impact of the Company’s fair value hedges as applicable. The fair values of the fixed rate notes disclosed in the following table were determined based on quoted prices from the broker/dealer market, observable market inputs for similarly termed treasury notes adjusted for the Company’s credit spread and inputs management believes a market participant would use in determining imputed interest for obligations without a stated interest rate (Level 2). The fair values of the revolving credit borrowings, securitized receivables and commercial paper approximate their carrying values (see Note 10). Carrying Value at Fair Value at Carrying Value at Fair Value at (In thousands) March 31, 2016 March 31, 2016 March 31, 2015 March 31, 2015 3.25% senior notes due 2015 $ — $ — $ 249,962 $ 252,520 2.95% senior notes due 2016 249,988 250,543 249,918 254,953 1.65% senior notes due 2018 324,796 324,942 324,688 323,921 2.375% senior notes due 2020 274,834 276,859 274,791 274,821 3.05% senior notes due 2020 399,328 410,416 — — 2.90% senior notes due 2022 249,815 250,555 249,787 249,028 3.65% senior notes due 2024 299,520 308,082 299,462 310,500

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	12 Months Ended
	Mar. 31, 2016
Stockholders' Equity Note [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table presents the gross and net changes in the balances within each component of AOCI for each of the years in the three-year period ended March 31, 2016 . (In thousands) Foreign Currency Translation Adjustments Treasury Rate Lock Agreement Total Accumulated Other Comprehensive Income (Loss) Balance at March 31, 2013 $ 5,253 $ (815 ) $ 4,438 Other comprehensive income (loss) before reclassifications (4,235 ) — (4,235 ) Amounts reclassified from AOCI (a) — 517 517 Tax effect of other comprehensive income items — (191 ) (191 ) Other comprehensive income (loss), net of tax (4,235 ) 326 (3,909 ) Balance at March 31, 2014 1,018 (489 ) 529 Other comprehensive income (loss) before reclassifications (15,708 ) — (15,708 ) Amounts reclassified from AOCI (a) — 517 517 Tax effect of other comprehensive income items — (191 ) (191 ) Other comprehensive income (loss), net of tax (15,708 ) 326 (15,382 ) Balance at March 31, 2015 (14,690 ) (163 ) (14,853 ) Other comprehensive income (loss) before reclassifications (3,712 ) — (3,712 ) Amounts reclassified from AOCI (a) — 259 259 Tax effect of other comprehensive income items — (96 ) (96 ) Other comprehensive income (loss), net of tax (3,712 ) 163 (3,549 ) Balance at March 31, 2016 $ (18,402 ) $ — $ (18,402 ) ___________________ (a) The reclassifications out of AOCI were associated with a loss on a treasury rate lock agreement from July 2010 related to the issuance of the Company’s 2015 Notes, which was being reclassified into earnings (interest expense) over the term of the 2015 Notes until their redemption in September 2015. The effects on the respective line items of the consolidated statements of earnings impacted by the reclassifications were not material for the twelve months ended March 31, 2016 , 2015 and 2014 .

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Mar. 31, 2016
Share-based Compensation, Allocation and Classification in Financial Statements [Abstract]
Schedule of Stock-Based Compensation Expense Recognized by Plan	The Company recognizes stock-based compensation expense for its equity incentive plan and employee stock purchase plan. The following table summarizes stock-based compensation expense recognized by the Company in each of the years in the three-year period ended March 31, 2016 . Years Ended March 31, (In thousands) 2016 2015 2014 Stock-based compensation expense related to: Equity Incentive Plan $ 24,464 $ 25,935 $ 24,892 Employee Stock Purchase Plan - options to purchase stock 3,293 4,092 4,069 27,757 30,027 28,961 Tax benefit (9,850 ) (10,624 ) (10,392 ) Stock-based compensation expense, net of tax $ 17,907 $ 19,403 $ 18,569
Schedule of Stock Option Grant Assumptions	The following assumptions were used by the Company in valuing the stock options grants issued in each fiscal year: Fiscal 2016 Fiscal 2015 Fiscal 2014 Expected volatility 24.8 % 34.3 % 40.5 % Expected dividend yield 2.31 % 2.06 % 1.95 % Expected term 5.6 years 5.6 years 5.6 years Risk-free interest rate 1.7 % 1.7 % 1.0 %
Summary of Stock Option Activity	The following table summarizes the stock option activity during the three years ended March 31, 2016 : Number of Stock Options Weighted-Average Exercise Price Aggregate Intrinsic Value (In thousands) Outstanding at March 31, 2013 5,052,016 $ 60.26 Granted 959,700 $ 102.96 Exercised (817,016 ) $ 47.38 Forfeited (90,276 ) $ 85.04 Outstanding at March 31, 2014 5,104,424 $ 69.91 $ 186,816 Granted 977,500 $ 104.80 Exercised (1,034,325 ) $ 53.49 Forfeited (73,929 ) $ 98.24 Outstanding at March 31, 2015 4,973,670 $ 79.76 $ 131,135 Granted 1,019,675 $ 103.57 Exercised (837,455 ) $ 62.06 Forfeited (91,550 ) $ 101.83 Outstanding at March 31, 2016 5,064,340 $ 87.08 $ 276,296 Vested or expected to vest at March 31, 2016 5,051,024 $ 87.04 $ 275,798 Exercisable at March 31, 2016 2,911,622 $ 75.47 $ 192,649
Schedule of ESPP Purchase Option Assumptions	The following assumptions were used by the Company in valuing the employees’ option to purchase shares of common stock under the ESPP: Fiscal 2016 Fiscal 2015 Fiscal 2014 Expected volatility 17.9 % 17.1 % 19.5 % Expected dividend yield 2.60 % 2.07 % 1.96 % Expected term 3 to 9 months 3 to 9 months 3 to 9 months Risk-free interest rate 0.04 % 0.06 % 0.08 %
Summary of ESPP Purchase Option Activity	The following table summarizes the activity of the ESPP during the three years ended March 31, 2016 : Number of Purchase Options Weighted-Average Exercise Price Aggregate Intrinsic Value (In thousands) Outstanding at March 31, 2013 62,137 $ 68.74 Granted 211,093 $ 82.88 Exercised (218,109 ) $ 79.38 Outstanding at March 31, 2014 55,121 $ 80.77 $ 1,419 Granted 200,030 $ 90.82 Exercised (201,037 ) $ 89.24 Outstanding at March 31, 2015 54,114 $ 86.47 $ 1,063 Granted 187,265 $ 78.93 Exercised (241,379 ) $ 81.26 Outstanding at March 31, 2016 — $ — $ — In accordance with the terms of the Merger Agreement, there were no outstanding purchase options at March 31, 2016 as the January 2016 purchase represented the final purchase under the ESPP, with no further grants of options to purchase common stock under the ESPP. As a result, all compensation expense related to the outstanding purchase options under the ESPP was recognized in full at December 31, 2015, and no additional expense was incurred related to the Company’s ESPP for the remainder of fiscal 2016.

Interest Expense, Net (Tables)

Interest Expense, Net (Tables)	12 Months Ended
	Mar. 31, 2016
Interest Expense [Abstract]
Schedule of Interest Expense, Net	Interest expense, net, consists of: Years Ended March 31, (In thousands) 2016 2015 2014 Interest expense $ 62,100 $ 64,191 $ 75,361 Interest and finance charge income (2,029 ) (1,959 ) (1,663 ) $ 60,071 $ 62,232 $ 73,698

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Computation Of Basic And Diluted Weighted Average Common Shares Outstanding	The table below presents the computation of basic and diluted weighted average common shares outstanding for the years ended March 31, 2016 , 2015 and 2014 : (In thousands, except per share amounts) Years Ended March 31, Basic Earnings per Share Computation 2016 2015 2014 Numerator: Net earnings $ 337,500 $ 368,086 $ 350,784 Denominator: Basic shares outstanding 73,422 74,702 73,623 Basic earnings per share $ 4.60 $ 4.93 $ 4.76 (In thousands, except per share amounts) Years Ended March 31, Diluted Earnings per Share Computation 2016 2015 2014 Numerator: Net earnings $ 337,500 $ 368,086 $ 350,784 Denominator: Basic shares outstanding 73,422 74,702 73,623 Incremental shares from assumed exercises and conversions: Stock options and options under the Employee Stock Purchase Plan 955 1,149 1,287 Diluted shares outstanding 74,377 75,851 74,910 Diluted earnings per share $ 4.54 $ 4.85 $ 4.68

Leases (Tables)

Leases (Tables)	12 Months Ended
	Mar. 31, 2016
Leases [Abstract]
Schedule of Future Minimum Lease Payments for Operating Leases	At March 31, 2016 , future minimum lease payments under non-cancelable operating leases were as follows: (In thousands) Years Ending March 31, 2017 $ 112,059 2018 94,419 2019 72,522 2020 53,725 2021 35,126 Thereafter 44,651 $ 412,502

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Future Commitments Under Take or Pay Supply Agreements	At March 31, 2016 , future commitments under take-or-pay supply agreements were as follows: (In thousands) Years Ending March 31, 2017 $ 212,212 2018 176,650 2019 136,203 2020 92,058 2021 45,613 Thereafter 198,069 $ 860,805

Supplemental Cash Flow Inform50

Supplemental Cash Flow Information (Tables)	12 Months Ended
	Mar. 31, 2016
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Paid for Interest and Income Taxes	Cash paid for interest and income taxes was as follows: Years Ended March 31, (In thousands) 2016 2015 2014 Interest paid $ 64,992 $ 62,986 $ 86,479 Income taxes, net of refunds 170,840 194,161 164,482
Schedule of Noncash or Part Noncash Acquisitions	Liabilities assumed and stock issued as a result of acquisitions were as follows: Years Ended March 31, (In thousands) 2016 2015 2014 Fair value of assets acquired $ 121,348 $ 66,626 $ 218,413 Net cash paid for acquisitions (a) (102,032 ) (51,827 ) (205,370 ) Stock issued for acquisition (b) — (4,458 ) — Liabilities assumed $ 19,316 $ 10,341 $ 13,043 ____________________ (a) Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions. (b) Represents shares of Airgas, Inc. common stock issued in connection with a single prior year acquisition.

Summary by Business Segment (Ta

Summary by Business Segment (Tables)	12 Months Ended
	Mar. 31, 2016
Segment Reporting, Measurement Disclosures [Abstract]
Schedule of Financial Information by Segment	Year Ended March 31, 2016 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,866,065 $ 631,646 $ (38,209 ) $ 3,459,502 Hardgoods 1,850,163 4,123 (11 ) 1,854,275 Net sales (a) 4,716,228 635,769 (38,220 ) 5,313,777 Cost of products sold (excluding depreciation) (a) 2,037,492 302,326 (38,220 ) 2,301,598 Selling, distribution and administrative expenses 1,828,814 213,940 — 2,042,754 Merger costs and other special charges — — 35,967 35,967 Depreciation 288,704 29,848 — 318,552 Amortization 29,403 4,792 — 34,195 Total costs and expenses 4,184,413 550,906 (2,253 ) 4,733,066 Operating income $ 531,815 $ 84,863 $ (35,967 ) $ 580,711 Assets $ 5,531,042 $ 603,914 $ — $ 6,134,956 Capital expenditures $ 426,290 $ 30,609 $ — $ 456,899 Year Ended March 31, 2015 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,823,297 $ 556,941 $ (29,219 ) $ 3,351,019 Hardgoods 1,950,192 3,681 (7 ) 1,953,866 Net sales (a) 4,773,489 560,622 (29,226 ) 5,304,885 Cost of products sold (excluding depreciation) (a) 2,092,466 292,635 (29,226 ) 2,355,875 Selling, distribution and administrative expenses 1,792,116 186,558 — 1,978,674 Depreciation 272,200 25,510 — 297,710 Amortization 27,373 3,975 — 31,348 Total costs and expenses 4,184,155 508,678 (29,226 ) 4,663,607 Operating income $ 589,334 $ 51,944 $ — $ 641,278 Assets $ 5,397,535 $ 576,075 $ — $ 5,973,610 Capital expenditures $ 438,867 $ 29,922 $ — $ 468,789 Year Ended March 31, 2014 (In thousands) Distribution All Other Ops. Eliminations and Other Total Gas and rent $ 2,717,272 $ 539,954 $ (30,404 ) $ 3,226,822 Hardgoods 1,841,518 4,200 (3 ) 1,845,715 Net sales (a) 4,558,790 544,154 (30,407 ) 5,072,537 Cost of products sold (excluding depreciation) (a) 1,996,065 281,916 (30,407 ) 2,247,574 Selling, distribution and administrative expenses 1,705,408 176,289 7,426 1,889,123 Depreciation 252,329 23,132 — 275,461 Amortization 25,512 4,333 — 29,845 Total costs and expenses 3,979,314 485,670 (22,981 ) 4,442,003 Operating income $ 579,476 $ 58,484 $ (7,426 ) $ 630,534 Assets $ 5,222,781 $ 570,533 $ — $ 5,793,314 Capital expenditures $ 317,066 $ 37,521 $ — $ 354,587 ____________________ (a) Amounts in the “Eliminations and Other” column represent the elimination of intercompany sales and associated gross profit on sales from the Company’s All Other Operations business segment to its Distribution business segment.

Supplementary Information (Un52

Supplementary Information (Unaudited) (Tables)	12 Months Ended
	Mar. 31, 2016
Selected Quarterly Financial Information [Abstract]
Summary of Unaudited Results of Operations for Each Fiscal Quarter	The following table summarizes the unaudited results of operations for each quarter of fiscal 2016 and 2015 : (In thousands, except per share amounts) First Second Third Fourth 2016 Net sales $ 1,349,710 $ 1,374,569 $ 1,295,414 $ 1,294,084 Operating income (b) 152,578 170,145 125,587 132,401 Net earnings 88,235 98,034 73,864 77,367 Basic earnings per share (a) $ 1.17 $ 1.33 $ 1.02 $ 1.07 Diluted earnings per share (a) $ 1.16 $ 1.31 $ 1.01 $ 1.05 2015 Net sales $ 1,313,587 $ 1,357,755 $ 1,331,820 $ 1,301,723 Operating income 155,081 175,781 162,886 147,530 Net earnings 88,852 98,312 93,199 87,723 Basic earnings per share (a) $ 1.20 $ 1.32 $ 1.25 $ 1.17 Diluted earnings per share (a) $ 1.18 $ 1.30 $ 1.23 $ 1.15 ____________________ (a) Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding in each quarter. Therefore, the sum of the quarterly earnings per share does not necessarily equal the full year earnings per share disclosed on the consolidated statements of earnings.
Schedule of Other Operating Cost and Expense, by Component, by Quarter	includes the following items: (In thousands) First Second Third Fourth 2016 Merger costs (Note 2) $ — $ — $ 21,393 $ 7,574 Special charges (Note 18) — — — 7,000

Summary of Significant Accoun53

Summary of Significant Accounting Policies (Details) $ in Thousands	12 Months Ended			363 Months Ended
	Mar. 31, 2016USD ($)employeeslocations	Mar. 31, 2015USD ($)	Mar. 31, 2014USD ($)	Mar. 31, 2016USD ($)employeesbusinesses_acquiredlocations
Significant Accounting Policies [Line Items]
Number of businesses acquired (more than) | businesses_acquired				480
Number of employees (more than) | employees	17,000			17,000
Number of locations | locations	1,100			1,100
Intangible asset residual value	$ 0			$ 0
Asset retirement obligation	$ 22,800	$ 20,400		$ 22,800
Credit terms period for customers, days	30 days
Distribution costs	$ 918,000	889,000	$ 850,000
Depreciation expense	318,552	297,710	275,461
Transportation equipment [Member]
Significant Accounting Policies [Line Items]
Depreciation expense	$ 33,000	$ 32,000	$ 32,000
Minimum [Member] | Computer software costs [Member]
Significant Accounting Policies [Line Items]
Plant and equipment, useful life	3 years
Minimum [Member] | Transportation equipment [Member]
Significant Accounting Policies [Line Items]
Plant and equipment, useful life	3 years
Minimum [Member] | Customer relationships [Member]
Significant Accounting Policies [Line Items]
Other intangible assets, useful life	7 years
Maximum [Member] | Computer software costs [Member]
Significant Accounting Policies [Line Items]
Plant and equipment, useful life	10 years
Maximum [Member] | Transportation equipment [Member]
Significant Accounting Policies [Line Items]
Plant and equipment, useful life	15 years
Maximum [Member] | Customer relationships [Member]
Significant Accounting Policies [Line Items]
Other intangible assets, useful life	25 years

Merger Agreement Details)

Merger Agreement Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2016	Mar. 31, 2015
Business Combinations [Abstract]
Common stock, par value	$ 0.01				$ 0.01	$ 0.01
Cash payment per share to Airgas stockholders	$ 143				$ 143
Merger costs	$ 7,574	$ 21,393	$ 0	$ 0	$ 28,967

Acquisitions (Acquisitions Narr

Acquisitions (Acquisitions Narrative) (Details) $ in Thousands		12 Months Ended			363 Months Ended
		Mar. 31, 2016USD ($)businesses_acquiredlocations	Mar. 31, 2015USD ($)businesses_acquired	Mar. 31, 2014USD ($)businesses_acquiredlocations	Mar. 31, 2016USD ($)businesses_acquiredlocations
Business Acquisition [Line Items]
Number of businesses acquired | businesses_acquired					480
Goodwill acquired during period	[1]	$ 48,815	$ 26,932
Number of locations | locations		1,100			1,100
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired | businesses_acquired		18	14	11
Historical annual sales of acquired businesses		$ 85,000	$ 55,000	$ 82,000
Business acquisition, transaction costs		2,300	1,700	1,500	$ 2,300
Net sales from current year acquisitions		45,000	27,000	33,000
Fair value of trade receivables acquired		6,100	6,200	8,900	6,100
Gross contractual amounts of acquired trade receivables		6,900	7,000	9,400	6,900
Goodwill acquired during period		48,600	25,100	93,300
Goodwill deductible for income tax purposes		44,400	20,900	89,700	$ 44,400
Series of Individually Immaterial Business Acquisitions [Member] | Customer relationships [Member]
Business Acquisition [Line Items]
Other intangible assets acquired		29,300	11,300	55,800
Series of Individually Immaterial Business Acquisitions [Member] | Non-competition agreements [Member]
Business Acquisition [Line Items]
Other intangible assets acquired		$ 7,600	$ 4,800	4,300
The Encompass Gas Group, Inc. [Member]
Business Acquisition [Line Items]
Historical annual sales of acquired businesses				$ 55,000
Number of locations | locations				11
[1]	Includes acquisitions completed during the respective year and adjustments made to prior year acquisitions.

Acquisitions (Summary of the Co

Acquisitions (Summary of the Consideration Transferred and the Fair Values of the Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Business Acquisition [Line Items]
Cash		$ 101,704	$ 51,382	$ 203,529
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill		1,364,770	1,313,644	1,289,896
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash	[1]	102,032	51,827	205,370
Airgas, Inc. common stock	[2]		4,458
Fair value of total consideration transferred			56,285
Recognized amounts of identifiable assets acquired and liabilities assumed
Current assets, net		10,760	9,708	14,640
Plant and equipment		24,947	13,824	48,173
Other intangible assets		36,826	16,162	60,190
Current liabilities		(11,463)	(5,815)	(4,722)
Non-current liabilities		(7,853)	(4,526)	(8,321)
Total identifiable net assets		53,217	29,353	109,960
Goodwill		48,815	26,932	95,410
Recognized amounts of identifiable assets acquired, goodwill, and liabilities assumed, net		102,032	$ 56,285	205,370
Number of shares of Airgas, Inc. common stock issued in connection with an acquisition			41,060
Distribution Business Segment [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill		1,143,706	$ 1,116,569	1,092,728
Distribution Business Segment [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash	[1]	58,018	50,774	204,957
Airgas, Inc. common stock	[2]		4,458
Fair value of total consideration transferred			55,232
Recognized amounts of identifiable assets acquired and liabilities assumed
Current assets, net		8,532	9,705	14,631
Plant and equipment		11,701	13,824	48,919
Other intangible assets		24,057	15,122	60,190
Current liabilities		(7,216)	(5,765)	(6,088)
Non-current liabilities		(3,856)	(4,526)	(8,321)
Total identifiable net assets		33,218	28,360	109,331
Goodwill		24,800	26,872	95,626
Recognized amounts of identifiable assets acquired, goodwill, and liabilities assumed, net		58,018	55,232	204,957
All Other Operations Business Segment [Member]
Recognized amounts of identifiable assets acquired and liabilities assumed
Goodwill		221,064	197,075	197,168
All Other Operations Business Segment [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Cash	[1]	44,014	1,053	413
Airgas, Inc. common stock	[2]		0
Fair value of total consideration transferred			1,053
Recognized amounts of identifiable assets acquired and liabilities assumed
Current assets, net		2,228	3	9
Plant and equipment		13,246	0	(746)
Other intangible assets		12,769	1,040	0
Current liabilities		(4,247)	(50)	1,366
Non-current liabilities		(3,997)	0	0
Total identifiable net assets		19,999	993	629
Goodwill		24,015	60	(216)
Recognized amounts of identifiable assets acquired, goodwill, and liabilities assumed, net		$ 44,014	$ 1,053	$ 413
[1]	Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions.
[2]	Represents 41,060 shares of Airgas, Inc. common stock issued in connection with a single acquisition. The fair value of the shares issued as part of the consideration for the acquisition was determined based on the closing sales price of Airgas, Inc. common stock on the acquisition date.

Acquisitions (Pro Forma Operati

Acquisitions (Pro Forma Operating Results) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
FY16 Acquisitions [Member]
Business Acquisition [Line Items]
Net sales	$ 5,335,812	$ 5,388,313
Net earnings	$ 338,408	$ 372,975
Diluted earnings per share	$ 4.55	$ 4.92
FY15 Acquisitions [Member]
Business Acquisition [Line Items]
Net sales		$ 5,327,458	$ 5,123,949
Net earnings		$ 368,305	$ 351,941
Diluted earnings per share		$ 4.86	$ 4.70

Inventories, Net (Details)

Inventories, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Inventories, Net [Line Items]
Inventories, net	$ 459,521	$ 474,070
Hardgoods [Member]
Inventories, Net [Line Items]
Inventories, net	309,897	311,453
Gases [Member]
Inventories, Net [Line Items]
Inventories, net	$ 149,624	$ 162,617

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Tax benefit from exercise of stock options	$ 13,500	$ 16,000	$ 13,700
Net operating loss carryforwards	11,070	12,061
Undistributed earnings of foreign subsidiaries	97,000
Unrecognized net income tax benefits	20,922	20,983	$ 18,224
Federal deferred tax assets associated with unrecognized state tax benefits	8,300
Unrecognized tax benefits, income tax penalties and interest accrued	$ 3,800	$ 4,700

Income Taxes (Earnings Before I

Income Taxes (Earnings Before Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
United States	$ 527,100	$ 572,182	$ 539,063
Foreign	2,617	11,939	12,842
Earnings before income taxes	$ 529,717	$ 584,121	$ 551,905

Income Taxes (Components of Inc

Income Taxes (Components of Income Tax Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Current [Abstract]
Federal	$ 148,585	$ 163,774	$ 184,308
Foreign	1,029	2,010	4,561
State	15,413	17,410	19,121
Total current income tax expense	165,027	183,194	207,990
Deferred [Abstract]
Federal	30,792	24,499	(4,722)
Foreign	(197)	2,604	(1,127)
State	(3,405)	5,738	(1,020)
Total deferred income tax expense	27,190	32,841	(6,869)
Income tax expense	$ 192,217	$ 216,035	$ 201,121

Income Taxes (Effective Income

Income Taxes (Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Income Tax Disclosure [Abstract]
Taxes at U.S. federal statutory rate	35.00%	35.00%	35.00%
Increase (decrease) in income taxes resulting from:
State income taxes, net of federal benefit	1.50%	2.60%	2.10%
Domestic production activities deduction	(1.20%)	(1.00%)	(1.00%)
Other, net	1.00%	0.40%	0.30%
Effective income tax rate	36.30%	37.00%	36.40%

Income Taxes (Deferred Tax Asse

Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Deferred Tax Assets
Inventories	$ 25,936	$ 27,697
Deferred rental income	17,670	17,986
Insurance reserves	12,410	14,157
Litigation settlement and other reserves	2,330	3,132
Asset retirement obligations	8,279	7,553
Stock-based compensation	36,357	33,538
Other	35,787	19,876
Net operating loss carryforwards	11,070	12,061
Valuation allowance	(1,141)	(671)
Deferred tax assets, net	148,698	135,329
Deferred Tax Liabilities
Plant and equipment	(732,503)	(711,840)
Intangible assets	227,809	207,690
Other	(12,822)	(12,301)
Deferred tax liabilities	(973,134)	(931,831)
Net deferred tax liability	$ (824,436)	$ (796,502)

Income Taxes (Deferred Tax As64

Income Taxes (Deferred Tax Assets and Liabilities by Balance Sheet Grouping) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Current deferred income tax asset, net	$ 69,908	$ 58,072
Non-current deferred income tax liability, net	(894,344)	(854,574)
Net deferred tax liability	$ (824,436)	$ (796,502)

Income Taxes (Unrecognized Net

Income Taxes (Unrecognized Net Income Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Beginning unrecognized net income tax benefits	$ 20,983	$ 18,224
Additions for current year tax positions	3,845	3,565
Additions for tax positions of prior years	187	1,288
Reductions for tax positions of prior years	(3,306)	(1,646)
Reductions for settlements with taxing authorities	0	(234)
Reductions as a result of expiration of applicable statutes of limitations	(787)	(214)
Ending unrecognized net income tax benefits	$ 20,922	$ 20,983

Plant and Equipment (Details)

Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Plant and Equipment [Line Items]
Plant and equipment at cost	$ 5,559,041	$ 5,305,059
Land and land improvements [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	246,820	225,721
Buildings and improvements [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	$ 634,816	581,076
Plant and equipment, useful life	25 years
Cylinders [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	$ 1,504,566	1,461,600
Plant and equipment, useful life	30 years
Bulk tank stations [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	$ 846,344	789,881
Rental equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	496,383	466,833
Machinery and equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	1,057,142	988,857
Computers, furniture and fixtures [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	296,408	338,316
Transportation equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	366,221	369,034
Construction in progress [Member]
Plant and Equipment [Line Items]
Plant and equipment at cost	$ 110,341	$ 83,741
Minimum [Member] | Bulk tank stations [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	10 years
Minimum [Member] | Rental equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	2 years
Minimum [Member] | Machinery and equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	7 years
Minimum [Member] | Computers, furniture and fixtures [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	3 years
Minimum [Member] | Transportation equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	3 years
Maximum [Member] | Bulk tank stations [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	30 years
Maximum [Member] | Rental equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	10 years
Maximum [Member] | Machinery and equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	10 years
Maximum [Member] | Computers, furniture and fixtures [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	10 years
Maximum [Member] | Transportation equipment [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	15 years
Weighted Average [Member] | Bulk tank stations [Member]
Plant and Equipment [Line Items]
Plant and equipment, useful life	17 years

Goodwill and Other Intangible67

Goodwill and Other Intangible Assets (Changes In Goodwill) (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Goodwill [Roll Forward]
Goodwill at period start date		$ 1,313,644	$ 1,289,896
Acquisitions	[1]	48,815	26,932
Other adjustments, including foreign currency translation		2,311	(3,184)
Goodwill at period end date		1,364,770	1,313,644
Distribution Business Segment [Member]
Goodwill [Roll Forward]
Goodwill at period start date		1,116,569	1,092,728
Acquisitions	[1]	24,800	26,872
Other adjustments, including foreign currency translation		2,337	(3,031)
Goodwill at period end date		1,143,706	1,116,569
All Other Operations Business Segment [Member]
Goodwill [Roll Forward]
Goodwill at period start date		197,075	197,168
Acquisitions	[1]	24,015	60
Other adjustments, including foreign currency translation		(26)	(153)
Goodwill at period end date		$ 221,064	$ 197,075
[1]	Includes acquisitions completed during the respective year and adjustments made to prior year acquisitions.

Goodwill and Other Intangible68

Goodwill and Other Intangible Assets (Annual Test for Goodwill Impairment) (Details)	Oct. 31, 2015reporting_units
Distribution Business Segment [Member]
Goodwill [Line Items]
Number of reporting units	21
All Other Operations Business Segment [Member]
Goodwill [Line Items]
Number of reporting units	6

Goodwill and Other Intangible69

Goodwill and Other Intangible Assets (Other Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Other intangible assets by major class
Gross carrying amount	$ 413,467	$ 389,209
Accumulated amortization	(165,295)	(144,690)
Net carrying amount	248,172	244,519
Amortization	34,195	31,348	$ 29,845
Estimated future amortization expense by fiscal year
Estimated future amortization expense in 2016	31,800
Estimated future amortization expense in 2017	29,500
Estimated future amortization expense in 2018	27,400
Estimated future amortization expense in 2019	25,900
Estimated future amortization expense in 2020	22,200
Estimated future amortization expense thereafter	111,400
Customer relationships [Member]
Other intangible assets by major class
Gross carrying amount	368,096	345,805
Accumulated amortization	(138,467)	(120,321)
Net carrying amount	229,629	225,484
Non-competition agreements [Member]
Other intangible assets by major class
Gross carrying amount	45,171	43,204
Accumulated amortization	(26,776)	(24,335)
Net carrying amount	18,395	18,869
Other intangible assets [Member]
Other intangible assets by major class
Gross carrying amount	200	200
Accumulated amortization	(52)	(34)
Net carrying amount	148	166
Customer relationships, non-competition agreements and other [Member]
Other intangible assets by major class
Amortization	$ 32,700	$ 30,000
Weighted Average [Member] | Customer relationships [Member]
Other intangible assets by major class
Other intangible assets, useful life	17 years	17 years
Weighted Average [Member] | Non-competition agreements [Member]
Other intangible assets by major class
Other intangible assets, useful life	6 years	6 years

Accrued Expenses and Other Cu70

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Mar. 31, 2015
Accrued Liabilities and Other Liabilities [Abstract]
Accrued payroll and employee benefits		$ 81,107	$ 98,547
Business insurance reserves	[1]	48,176	49,934
Taxes other than income taxes		22,160	22,863
Cash overdraft		72,282	71,537
Deferred rental revenue		34,440	34,538
Accrued interest		10,855	12,860
Other accrued expenses and current liabilities		79,668	56,600
Accrued expenses and other current liabilities (Note 8)		348,688	346,879
Insurance receivables		$ 9,900	$ 11,600
[1]	With respect to the business insurance reserves above, the Company had corresponding insurance receivables of $9.9 million at March 31, 2016 and $11.6 million at March 31, 2015, which are included within the “Prepaid expenses and other current assets” line item on the Company’s consolidated balance sheets. The insurance receivables represent the balance of probable claim losses in excess of the Company’s deductible for which the Company is fully insured.

Indebtedness (Schedule of Debt)

Indebtedness (Schedule of Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Short-term debt	$ 383,258	$ 325,871
Long-term debt	2,204,927	1,998,772
Less current portion of long-term debt	(250,107)	(250,110)
Long-term debt, excluding current portion	1,954,820	1,748,662
Total debt	2,588,185	2,324,643
Money market loans [Member]
Debt Instrument [Line Items]
Short-term debt	0	0
Commercial paper [Member]
Debt Instrument [Line Items]
Short-term debt	383,258	325,871
Trade receivables securitization [Member]
Debt Instrument [Line Items]
Long-term debt	330,000	295,000
Revolving credit borrowings - U.S. [Member]
Debt Instrument [Line Items]
Long-term debt	0	0
Revolving credit borrowings - Multi-currency [Member]
Debt Instrument [Line Items]
Long-term debt	70,259	48,332
Revolving credit borrowings - France [Member]
Debt Instrument [Line Items]
Long-term debt	6,088	6,277
Senior notes, net [Member]
Debt Instrument [Line Items]
Long-term debt	1,798,282	1,648,608
Other long-term debt [Member]
Debt Instrument [Line Items]
Long-term debt	$ 298	$ 555

Indebtedness (Money Market Loan

Indebtedness (Money Market Loans Narrative) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Short-term debt	$ 383,258,000	$ 325,871,000
Money market loans [Member]
Debt Instrument [Line Items]
Short-term debt	0	$ 0
Money market loans [Member] | Agreement expiring in December 2016 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 0
Short-term debt, terms	advances may be for one to six months with rates at a fixed spread over the corresponding London Interbank Offering Rate (“LIBOR”)
Money market loans [Member] | Agreement expiring in July 2016 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 0
Short-term debt, terms	advances are generally overnight or for up to seven days. The amount, term and interest rate of an advance are established through mutual agreement with the financial institution when the Company requests such an advance
Maximum [Member] | Money market loans [Member] | Agreement expiring in December 2016 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 35,000,000
Short-term debt maturity period	6 months
Maximum [Member] | Money market loans [Member] | Agreement expiring in July 2016 [Member]
Debt Instrument [Line Items]
Short-term debt	$ 35,000,000
Short-term debt maturity period	7 days
Minimum [Member] | Money market loans [Member] | Agreement expiring in December 2016 [Member]
Debt Instrument [Line Items]
Short-term debt maturity period	1 month

Indebtedness (Commercial Paper

Indebtedness (Commercial Paper Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Short-term Debt [Line Items]
Short-term debt	$ 383,258	$ 325,871
Commercial paper [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity	$ 1,000,000
Short-term debt, terms	maturities that vary, but will generally not exceed 90 days from the date of issue
Short-term debt	$ 383,258	$ 325,871
Short-term debt, weighted average interest rate		0.79%
Maximum [Member] | Commercial paper [Member]
Short-term Debt [Line Items]
Short-term debt maturity period	90 days

Indebtedness (Trade Receivables

Indebtedness (Trade Receivables Securitization Narrative) (Details) - Trade receivables securitization [Member]	12 Months Ended
	Mar. 31, 2016USD ($)banks	Jul. 24, 2015USD ($)banks
Debt Instrument [Line Items]
Number of commercial banks participating in trade securitization agreement | banks	4	3
Trade Receivables Securitization, Maximum Borrowing Amount	$ 330,000,000	$ 295,000,000
Basis spread on variable rate	0.75%
Maximum [Member]
Debt Instrument [Line Items]
Trade receivables securitization	$ 330,000,000

Indebtedness (Senior Credit Fac

Indebtedness (Senior Credit Facility Narrative) (Details) € in Millions, $ in Millions	12 Months Ended
	Mar. 31, 2016USD ($)	Mar. 31, 2016EUR (€)
Debt Instrument [Line Items]
Letters of credit outstanding	$ 51
Revolving credit facility [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	1,000
Line of credit facility, increase, additional borrowings, maximum	500
Line of credit facility, outstanding borrowings	70
Line of credit facility, remaining borrowing capacity	495
Revolving credit borrowings - US [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	875
Line of credit facility, outstanding borrowings	$ 0
Basis spread on variable rate	1.25%
Line of credit facility, unused capacity, commitment fee percentage	0.15%
Revolving credit borrowings - Multi-currency [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 125
Line of credit facility, increase, additional borrowings, maximum	50
Line of credit facility, outstanding borrowings	$ 70
Basis spread on variable rate	1.25%
Line of credit facility, interest rate at period end	1.90%	1.90%
Line of credit facility, unused capacity, commitment fee percentage	0.15%
Revolving credit borrowings - France [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 9.1	€ 8
Line of credit facility, outstanding borrowings	$ 6.1	€ 5.3
Basis spread on variable rate	1.25%
Letter of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 100
Swingline [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 75

Indebtedness (Senior Notes Narr

Indebtedness (Senior Notes Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Debt Instrument [Line Items]
Long-term debt		$ 2,204,927	$ 1,998,772
3.25% senior notes due October 2015 [Member]
Debt Instrument [Line Items]
Long-term debt		0	249,962
2.95% senior notes due June 2016 [Member]
Debt Instrument [Line Items]
Long-term debt		249,988	249,918
1.65% senior notes due February 2018 [Member]
Debt Instrument [Line Items]
Long-term debt		324,796	324,688
2.375% senior notes due February 2020 [Member]
Debt Instrument [Line Items]
Long-term debt		274,834	274,791
3.05% senior notes due August 2020 Member [Member]
Debt Instrument [Line Items]
Long-term debt		399,328	0
2.90% senior notes due November 2022 [Member]
Debt Instrument [Line Items]
Long-term debt		249,815	249,787
3.65% senior notes due July 2024 [Member]
Debt Instrument [Line Items]
Long-term debt		299,520	299,462
Senior notes, net [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		1,800,000	1,650,000
Debt instrument, unamortized discount		(1,718)	(1,392)
Long-term debt		$ 1,798,282	1,648,608
Debt instrument, redemption, description		the Company has the option to redeem the Senior Notes prior to their maturity, in whole or in part, at 100% of the principal plus any accrued but unpaid interest or at the applicable make-whole premium.
Senior notes, net [Member] | 3.25% senior notes due October 2015 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	[1]	3.25%
Debt instrument, interest rate, effective percentage	[1]	3.283%
Debt instrument, frequency of periodic payment		April 1 and October 1
Debt instrument, face amount	[1]	$ 0	250,000
Senior notes, net [Member] | 2.95% senior notes due June 2016 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage	[2]	2.98%
Debt instrument, frequency of periodic payment		June 15 and December 15
Debt instrument, face amount	[2]		250,000
Senior notes, net [Member] | 1.65% senior notes due February 2018 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		1.65%
Debt instrument, interest rate, effective percentage		1.685%
Debt instrument, frequency of periodic payment		February 15 and August 15
Debt instrument, face amount		$ 325,000	325,000
Senior notes, net [Member] | 2.375% senior notes due February 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		2.375%
Debt instrument, interest rate, effective percentage		2.392%
Debt instrument, frequency of periodic payment		February 15 and August 15
Debt instrument, face amount		$ 275,000	275,000
Senior notes, net [Member] | 3.05% senior notes due August 2020 Member [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	[3]	3.05%
Debt instrument, interest rate, effective percentage	[3]	3.092%
Debt instrument, frequency of periodic payment		February 1 and August 1
Debt instrument, face amount	[3]	$ 400,000	0
Senior notes, net [Member] | 2.90% senior notes due November 2022 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		2.90%
Debt instrument, interest rate, effective percentage		2.913%
Debt instrument, frequency of periodic payment		May 15 and November 15
Debt instrument, face amount		$ 250,000	250,000
Senior notes, net [Member] | 3.65% senior notes due July 2024 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage		3.65%
Debt instrument, interest rate, effective percentage		3.673%
Debt instrument, frequency of periodic payment		January 15 and July 15
Debt instrument, face amount		$ 300,000	$ 300,000
[1]	On September 14, 2015, the Company redeemed in full its 2015 Notes senior notes originally due to mature on October 1, 2015.
[2]	The 2016 Notes are included within the “Current portion of long-term debt” line item on the Company’s consolidated balance sheet based on the maturity date.
[3]	On August 11, 2015, the Company issued the 2020 B Notes. The net proceeds from the sale of the 2020 Notes were used for general corporate purposes, including to fund acquisitions, to repay indebtedness and to repurchase shares pursuant to the Company’s stock repurchase program. Interest payments on the 2020 Notes commenced on February 1, 2016.

Indebtedness (Debt Extinguishme

Indebtedness (Debt Extinguishment Charge Narrative) (Details) - USD ($) $ in Thousands	Oct. 02, 2013	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Extinguishment of Debt [Line Items]
Loss on the extinguishment of debt		$ 0	$ 0	$ (9,150)
Senior subordinated notes [Member]
Extinguishment of Debt [Line Items]
Extinguishment of debt, amount	$ 215,000
Debt instrument, interest rate, stated percentage	7.125%
Debt instrument, redemption price, percentage	103.563%
Loss on the extinguishment of debt			$ (9,100)

Indebtedness (Schedule of Long-

Indebtedness (Schedule of Long-Term Debt Maturities) (Details) - USD ($) $ in Thousands		Mar. 31, 2016	Mar. 31, 2015
Years Ending March 31, [Abstract]
2,016	[1]	$ 250,118
2,017	[1]	325,175
2,018	[1]	330,004
2,019	[1]	351,348
2,020	[1]	400,000
Thereafter	[1]	550,000
Total maturities of long-term debt	[1]	2,206,645
Senior notes, net [Member]
Years Ending March 31, [Abstract]
Unamortized discounts		$ 1,718	$ 1,392
[1]	Outstanding borrowings under the Securitization Agreement at March 31, 2016 are reflected as maturing at the agreement’s expiration in December 2018.The Senior Notes are reflected in the debt maturity schedule at their maturity values rather than their carrying values, which are net of aggregate discounts of $1.7 million at March 31, 2016.

Derivative Instruments and He79

Derivative Instruments and Hedging Activities (Narrative) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Sep. 30, 2010USD ($)	Mar. 31, 2016USD ($)derivative_instruments	Mar. 31, 2015USD ($)derivative_instruments	Mar. 31, 2014USD ($)	Oct. 01, 2013USD ($)derivative_instruments	Jul. 30, 2010USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate derivatives held | derivative_instruments		0	0
Description of derivative activity volume		There were no outstanding derivative instruments on the Company’s consolidated balance sheets at March 31, 2016 or 2015, nor any derivative instruments used by the Company during the years ended March 31, 2016 or 2015.
Treasury Lock [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount						$ 100,000
Derivative instruments, loss recognized in other comprehensive income (loss), effective portion	$ 2,600
Derivative instruments, loss recognized in other comprehensive income (loss), effective portion, net of tax	$ 1,600
Derivative instruments, loss reclassified from accumulated OCI into income, effective portion		$ 259	$ 517	$ 517
Interest Rate Swap [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount					$ 300,000
Number of interest rate derivatives held | derivative_instruments					5
Two Point Eight Five Percent Senior Notes Due October Two Thousand Thirteen Member | Senior notes, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, amount of hedged item					$ 300,000
Debt instrument, interest rate, stated percentage					2.85%

Derivative Instruments and He80

Derivative Instruments and Hedging Activities (Effect on Earnings) (Details) - Interest Rate Swap [Member] - Interest Expense [Member] - Fair Value Hedging [Member] $ in Thousands	12 Months Ended
	Mar. 31, 2014USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of variable interest rate swaps	$ (2,490)
Change in carrying value of 2013 Notes	2,496
Net effect	$ 6

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value on a Recurring Basis) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan assets	$ 17,731	$ 16,288
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	17,731	16,288
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan assets	17,731	16,288
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	17,731	16,288
Fair Value, Measurements, Recurring [Member] | Quoted prices in active markets Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan assets	17,731	16,288
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	17,731	16,288
Fair Value, Measurements, Recurring [Member] | Significant other observable inputs Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Significant unobservable inputs Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Deferred compensation plan assets	0	0
Liabilities, Fair Value Disclosure [Abstract]
Deferred compensation plan liabilities	$ 0	$ 0

Fair Value Measurements (Carryi

Fair Value Measurements (Carrying Value and Fair Value of Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	$ 2,204,927	$ 1,998,772
3.25% senior notes due October 2015 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	0	249,962
Long-term debt, fair value	0	252,520
2.95% senior notes due June 2016 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	249,988	249,918
Long-term debt, fair value	250,543	254,953
1.65% senior notes due February 2018 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	324,796	324,688
Long-term debt, fair value	324,942	323,921
2.375% senior notes due February 2020 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	274,834	274,791
Long-term debt, fair value	276,859	274,821
3.05% senior notes due August 2020 Member [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	399,328	0
Long-term debt, fair value	410,416	0
2.90% senior notes due November 2022 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	249,815	249,787
Long-term debt, fair value	250,555	249,028
3.65% senior notes due July 2024 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, carrying value	299,520	299,462
Long-term debt, fair value	$ 308,082	$ 310,500

Stockholders' Equity (Common St

Stockholders' Equity (Common Stock) (Details) - $ / shares	Mar. 31, 2016	Mar. 31, 2015
Stockholders' Equity Note [Abstract]
Common stock, shares authorized	200,000,000	200,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares, outstanding	72,600,000	75,400,000
Treasury stock, shares	15,151,000	12,197,000

Stockholders' Equity (Preferred

Stockholders' Equity (Preferred Stock and Redeemable Preferred Stock) (Details) - shares	Mar. 31, 2016	Mar. 31, 2015
Class of Stock [Line Items]
Preferred stock, shares authorized	20,030,000	20,030,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Series A Junior Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	200,000
Series B Junior Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	200,000
Series C Junior Participating Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	200,000
Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, shares authorized	30,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0

Stockholders' Equity (Dividends

Stockholders' Equity (Dividends) (Details) - $ / shares	3 Months Ended												12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity Note [Abstract]
Cash dividends paid	$ 0.60	$ 0.60	$ 0.60	$ 0.60	$ 0.55	$ 0.55	$ 0.55	$ 0.55	$ 0.48	$ 0.48	$ 0.48	$ 0.48	$ 2.40	$ 2.20	$ 1.92

Stockholders' Equity (Stockhold

Stockholders' Equity (Stockholder Rights Plan) (Details)	12 Months Ended
	Mar. 31, 2016rights$ / sharesshares	Nov. 17, 2015
Stockholder Rights [Line Items]
Number of rights per each share of common stock | rights	1
Days after acquisition of certain percentage of company common stock that rights become exercisable	10 days
Number of business days for rights to become exercisable after tender or exchange offer	10 days
Market value of stock purchased with stockholder rights, in relation to exercise price	200.00%
Entity's optional redemption price per right	$ 0.0001
Percentage Of Outstanding Common Stock Beneficially Owned To Trigger Rights Plan	10.00%
Series C Junior Participating Preferred Stock [Member]
Stockholder Rights [Line Items]
Number of shares called by each right | shares	0.0001
Exercise price of rights	$ 230
Any Person or Group Other Than Peter McCausland [Member]
Stockholder Rights [Line Items]
Percentage of outstanding common stock that needs to be purchased to make rights exercisable		15.00%
Percentage of outstanding common stock to be acquired in a tender offer or exchange offer		15.00%
Percentage of outstanding common stock that if acquired would entitle the holder to purchase common stock with a market value equal to twice the exercise price		15.00%
Peter McCausland or Affiliated Group [Member]
Stockholder Rights [Line Items]
Percentage of outstanding common stock that needs to be purchased to make rights exercisable		20.00%
Percentage of outstanding common stock to be acquired in a tender offer or exchange offer		20.00%
Percentage of outstanding common stock that if acquired would entitle the holder to purchase common stock with a market value equal to twice the exercise price		20.00%

Stockholders' Equity (Stock Rep

Stockholders' Equity (Stock Repurchase Program) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	10 Months Ended
	Mar. 31, 2016	May. 28, 2015
Stockholders' Equity Note [Abstract]
Stock repurchase program, authorized amount		$ 500
Treasury stock, shares repurchased	3.8
Treasury Stock Acquired, Average Cost Per Share	$ 99.54
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 125

Stockholders' Equity (Comprehen

Stockholders' Equity (Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity Note [Abstract]
Comprehensive income	$ 333,951	$ 352,704	$ 346,875

Stockholders' Equity (Changes i

Stockholders' Equity (Changes in Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		$ (14,853)	$ 529	$ 4,438
Other comprehensive income (loss) before reclassifications		(3,712)	(15,708)	(4,235)
Amounts reclassified from AOCI	[1]	259	517	517
Tax effect of other comprehensive income items		(96)	(191)	(191)
Other comprehensive income (loss), net of tax		(3,549)	(15,382)	(3,909)
Ending balance		(18,402)	(14,853)	529
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(14,690)	1,018	5,253
Other comprehensive income (loss) before reclassifications		(3,712)	(15,708)	(4,235)
Amounts reclassified from AOCI	[1]	0	0	0
Tax effect of other comprehensive income items		0	0	0
Other comprehensive income (loss), net of tax		(3,712)	(15,708)	(4,235)
Ending balance		(18,402)	(14,690)	1,018
Treasury Rate Lock Agreement [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance		(163)	(489)	(815)
Other comprehensive income (loss) before reclassifications		0	0	0
Amounts reclassified from AOCI	[1]	259	517	517
Tax effect of other comprehensive income items		(96)	(191)	(191)
Other comprehensive income (loss), net of tax		163	326	326
Ending balance		$ 0	$ (163)	$ (489)
[1]	The reclassifications out of AOCI were associated with a loss on a treasury rate lock agreement from July 2010 related to the issuance of the Company’s 2015 Notes, which was being reclassified into earnings (interest expense) over the term of the 2015 Notes until their redemption in September 2015. The effects on the respective line items of the consolidated statements of earnings impacted by the reclassifications were not material for the twelve months ended March 31, 2016, 2015 and 2014.

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Aug. 14, 2012	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash payment per share to Airgas stockholders		$ 143
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Increase in maximum number of shares available for issuance	4,000
Shares authorized		11,900
Shares available for issuance		2,300
Maximum contractual term of awards		8 years
Weighted-average grant date fair value of stock options granted		$ 19.87	$ 28.72	$ 32.41
Total intrinsic value of stock options exercised		$ 52,500	$ 60,800	$ 47,000
Weighted-average remaining contractual term of stock options outstanding		4 years 7 months
Unrecognized compensation expense related to non-vested stock options		$ 35,300
Weighted-average vesting period of non-vested stock options (in years)		1 year 7 months
Stock Options [Member] | Share-based Compensation Award, Year One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage		25.00%
Stock Options [Member] | Share-based Compensation Award, Year Two [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage		25.00%
Stock Options [Member] | Share-based Compensation Award, Year Three [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage		25.00%
Stock Options [Member] | Share-Based Compensation Award, Year Four [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Annual vesting percentage		25.00%
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized		5,500
Shares available for issuance		900
Maximum contractual term of awards		12 months
Weighted-average grant date fair value of stock options granted		$ 17.59	$ 20.44	$ 19.27
Annual gross earnings withheld, maximum		15.00%
Percentage of market price employees pay for Company stock in ESPP		85.00%
Employee aggregate annual purchase limit maximum - ESPP		$ 25

Stock-Based Compensation (Stock

Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Stock-based compensation expense related to:
Stock-based compensation expense	$ 27,757	$ 30,027	$ 28,961
Tax benefit	(9,850)	(10,624)	(10,392)
Stock-based compensation expense, net of tax	17,907	19,403	18,569
Stock Options [Member]
Stock-based compensation expense related to:
Stock-based compensation expense	24,464	25,935	24,892
Employee Stock Purchase Plan [Member]
Stock-based compensation expense related to:
Stock-based compensation expense	$ 3,293	$ 4,092	$ 4,069

Stock-Based Compensation (Sto92

Stock-Based Compensation (Stock Option Grant Assumptions) (Details) - Stock Options [Member]	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	24.80%	34.30%	40.50%
Expected dividend yield	2.31%	2.06%	1.95%
Expected term, average years	5 years 7 months	5 years 7 months	5 years 7 months
Risk-free interest rate	1.70%	1.70%	1.00%

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary of Stock Option Activity) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at the beginning of period, number of options	4,973,670	5,104,424	5,052,016
Granted, number of options	1,019,675	977,500	959,700
Exercised, number of options	(837,455)	(1,034,325)	(817,016)
Forfeited, number of options	(91,550)	(73,929)	(90,276)
Outstanding at the end of period, number of options	5,064,340	4,973,670	5,104,424
Vested or expected to vest as of March 31, 2016, number of options	5,051,024
Exercisable as of March 31, 2016, number of options	2,911,622
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at the beginning of period, weighted-average exercise price per share	$ 79.76	$ 69.91	$ 60.26
Granted, weighted-average exercise price per share	103.57	104.80	102.96
Exercised, weighted-average exercise price per share	62.06	53.49	47.38
Forfeited, weighted-average exercise price per share	101.83	98.24	85.04
Outstanding at the end of period, weighted-average exercise price per share	87.08	$ 79.76	$ 69.91
Vested or expected to vest as of March 31, 2016, weighted-average exercise price per share	87.04
Exercisable at March 31, 2016, weighted-average exercise price per share	$ 75.47
Outstanding at the end of period, aggregate intrinsic value	$ 276,296	$ 131,135	$ 186,816
Vested or expected to vest as of March 31, 2016, aggregate intrinsic value	275,798
Exercisable as of March 31, 2016, aggregate intrinsic value	$ 192,649

Stock-Based Compensation (ESPP

Stock-Based Compensation (ESPP Purchase Option Assumptions) (Details) - Employee Stock Purchase Plan [Member]	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	17.90%	17.10%	19.50%
Expected dividend yield	2.60%	2.07%	1.96%
Risk-free interest rate	0.04%	0.06%	0.08%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term, months	3 months	3 months	3 months
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term, months	9 months	9 months	9 months

Stock-Based Compensation (ESP95

Stock-Based Compensation (ESPP - Purchase Option Activity) (Details) - Employee Stock Purchase Plan [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
ESPP Purchase Option Activity [Roll Forward]
Outstanding at the beginning of period, number of options	54,114	55,121	62,137
Granted, number of options	187,265	200,030	211,093
Exercised, number of options	(241,379)	(201,037)	(218,109)
Outstanding at the end of period, number of options	0	54,114	55,121
Share-based Compensation Arrangement by Share-based Payment Award, ESPP Purchase Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at the beginning of period, weighted-average exercise price per share	$ 86.47	$ 80.77	$ 68.74
Granted, weighted-average exercise price per share	78.93	90.82	82.88
Exercised, weighted-average exercise price per share	81.26	89.24	79.38
Outstanding at the end of period, weighted-average exercise price per share	$ 0	$ 86.47	$ 80.77
Outstanding at the end of period, aggregate intrinsic value	$ 0	$ 1,063	$ 1,419

Interest Expense, Net (Schedule

Interest Expense, Net (Schedule of Interest Expense, Net) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Interest Expense [Abstract]
Interest expense	$ 62,100	$ 64,191	$ 75,361
Interest and finance charge income	(2,029)	(1,959)	(1,663)
Interest expense, net	$ 60,071	$ 62,232	$ 73,698

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Anti-dilutive securities excluded from the Company's diluted earnings per share																	1,900	1,700	1,500
Net earnings	$ 77,367		$ 73,864		$ 98,034		$ 88,235		$ 87,723		$ 93,199		$ 98,312		$ 88,852		$ 337,500	$ 368,086	$ 350,784
Basic shares outstanding																	73,422	74,702	73,623
Basic earnings per share	$ 1.07	[1]	$ 1.02	[1]	$ 1.33	[1]	$ 1.17	[1]	$ 1.17	[1]	$ 1.25	[1]	$ 1.32	[1]	$ 1.20	[1]	$ 4.60	$ 4.93	$ 4.76
Incremental shares from assumed exercises of stock options and options under the ESPP																	955	1,149	1,287
Diluted shares outstanding																	74,377	75,851	74,910
Diluted earnings per share	$ 1.05	[1]	$ 1.01	[1]	$ 1.31	[1]	$ 1.16	[1]	$ 1.15	[1]	$ 1.23	[1]	$ 1.30	[1]	$ 1.18	[1]	$ 4.54	$ 4.85	$ 4.68
[1]	Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding in each quarter. Therefore, the sum of the quarterly earnings per share does not necessarily equal the full year earnings per share disclosed on the consolidated statements of earnings.

Leases (Narrative) (Details) (D

Leases (Narrative) (Details) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Leases [Abstract]
Operating leases, rent expense net	$ 130	$ 121	$ 110
Guaranteed residual value of fleet leases	$ 32
Residual value as percentage of original cost	9.80%

Leases (Future Minimum Lease Pa

Leases (Future Minimum Lease Payments) (Details) $ in Thousands	Mar. 31, 2016USD ($)
Years Ending March 31,
2,016	$ 112,059
2,017	94,419
2,018	72,522
2,019	53,725
2,020	35,126
Thereafter	44,651
Future minimum lease payments total	$ 412,502

Commitments and Contingencie100

Commitments and Contingencies (Litigation) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015
Litigation [Abstract]
Doral loss contingency, recorded in period	$ 7,000	$ 7,000	$ 0	$ 0	$ 0

Commitments and Contingencie101

Commitments and Contingencies (Merger Agreement) (Details) - USD ($) $ in Thousands	3 Months Ended				12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2016
Merger Agreement [Abstract]
Merger costs	$ 7,574	$ 21,393	$ 0	$ 0	$ 28,967

Commitments and Contingencie102

Commitments and Contingencies (Insurance Coverage) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Loss Contingencies [Line Items]
Business insurance programs high deductible limits per occurrence		$ 1	$ 1	$ 1
Self-insured medical benefits reserve		$ 14	$ 13.8
Scenario, Forecast [Member]
Loss Contingencies [Line Items]
Business insurance programs high deductible limits per occurrence	$ 1

Commitments and Contingencie103

Commitments and Contingencies (Supply Agreements) (Details) $ in Thousands	Mar. 31, 2016USD ($)suppliers
Unrecorded Unconditional Purchase Obligation[Line Items]
Annual commitment over next fiscal year for unrecorded unconditional purchase obligations	$ 212,212
Air Products [Member] | Bulk Gases [Member]
Unrecorded Unconditional Purchase Obligation[Line Items]
Annual commitment over next fiscal year for unrecorded unconditional purchase obligations	61,000
Linde AG [Member] | Bulk Gases [Member]
Unrecorded Unconditional Purchase Obligation[Line Items]
Annual commitment over next fiscal year for unrecorded unconditional purchase obligations	95,000
Other Producers [Member] | Bulk Gases [Member]
Unrecorded Unconditional Purchase Obligation[Line Items]
Annual commitment over next fiscal year for unrecorded unconditional purchase obligations	36,000
Other Producers [Member] | Liquid Carbon Dioxide [Member]
Unrecorded Unconditional Purchase Obligation[Line Items]
Annual commitment over next fiscal year for unrecorded unconditional purchase obligations	$ 20,000
Number of suppliers | suppliers	12

Commitments and Contingencie104

Commitments and Contingencies (Future Commitments Under Take or Pay Supply Agreements) (Details) $ in Thousands	Mar. 31, 2016USD ($)
Years Ending March 31, [Abstract]
2,016	$ 212,212
2,017	176,650
2,018	136,203
2,019	92,058
2,020	45,613
Thereafter	198,069
Future commitments under take-or-pay supply agreements	$ 860,805

Commitments and Contingencie105

Commitments and Contingencies (Construction Commitments) (Details) - Capital Addition Purchase Commitments [Member] $ in Millions	Mar. 31, 2016USD ($)customers
Long-term Purchase Commitment [Line Items]
Construction commitments | $	$ 48
Number of customers | customers	2

Commitments and Contingencie106

Commitments and Contingencies (Letters of Credit) (Details) $ in Millions	Mar. 31, 2016USD ($)
Commitments and Contingencies Disclosure [Abstract]
Letters of credit outstanding	$ 51

Benefit Plans (401K Plan) (Deta

Benefit Plans (401K Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Employer contributions to 401(k) plan	$ 14	$ 13	$ 12.3
Maximum [Member]
Defined Contribution Plan Disclosure [Line Items]
Defined contribution plan employer contributions, percentage of participants' wages	2.00%

Benefit Plans (Deferred Compens

Benefit Plans (Deferred Compensation Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Deferred compensation plan assets	$ 17,731	$ 16,288
Deferred compensation plan liabilities	$ 17,731	$ 16,288
Maximum [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Salary contribution to deferred compensation plan, percentage	75.00%
Bonus contribution to deferred compensation plan, percentage	100.00%

Related Parties (Details)

Related Parties (Details) - USD ($) $ in Millions	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Related Party Transactions [Abstract]
Payments to related parties	$ 5	$ 4.2	$ 4.1

Supplemental Cash Flow Infor110

Supplemental Cash Flow Information (Cash Paid For Interest And Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Supplemental Cash Flow Information [Abstract]
Interest paid	$ 64,992	$ 62,986	$ 86,479
Income taxes, net of refunds	$ 170,840	$ 194,161	$ 164,482

Supplemental Cash Flow Infor111

Supplemental Cash Flow Information (Noncash Investing and Financing Activities) (Details) - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Noncash or Part Noncash Acquisitions [Line Items]
Net cash paid for acquisitions		$ (101,704)	$ (51,382)	$ (203,529)
Series of Individually Immaterial Business Acquisitions [Member]
Noncash or Part Noncash Acquisitions [Line Items]
Fair value of assets acquired		121,348	66,626	218,413
Net cash paid for acquisitions	[1]	(102,032)	(51,827)	(205,370)
Stock issued for acquisition	[2]	0	(4,458)	0
Liabilities assumed		$ 19,316	$ 10,341	$ 13,043
[1]	Includes cash paid, net of cash acquired, for current year acquisitions as well as payments for the settlement of holdback liabilities and contingent consideration arrangements associated with prior year acquisitions.
[2]	Represents shares of Airgas, Inc. common stock issued in connection with a single prior year acquisition.

Summary by Business Segment (Na

Summary by Business Segment (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Selling, distribution and administrative expenses									$ 2,042,754	$ 1,978,674	$ 1,889,123
Number of business segments	2								2
Net sales	$ 1,294,084	$ 1,295,414	$ 1,374,569	$ 1,349,710	$ 1,301,723	$ 1,331,820	$ 1,357,755	$ 1,313,587	$ 5,313,777	5,304,885	5,072,537
Foreign [Member]
Segment Reporting Information [Line Items]
Net sales									88,000	93,000	88,000
Long-lived assets	$ 137,000				$ 143,000				137,000	143,000	148,000
Gas and Rent [Member]
Segment Reporting Information [Line Items]
Net sales									3,459,502	3,351,019	3,226,822
Hardgoods [Member]
Segment Reporting Information [Line Items]
Net sales									$ 1,854,275	$ 1,953,866	$ 1,845,715
Distribution Business Segment [Member]
Segment Reporting Information [Line Items]
Number of reportable segments									1
Number of operating segments									21
Sales, percentage of total									90.00%	90.00%	90.00%
Distribution Business Segment [Member] | Gas and Rent [Member]
Segment Reporting Information [Line Items]
Sales, percentage of total									61.00%	59.00%	60.00%
Distribution Business Segment [Member] | Hardgoods [Member]
Segment Reporting Information [Line Items]
Sales, percentage of total									39.00%	41.00%	40.00%
All Other Operations Business Segment [Member]
Segment Reporting Information [Line Items]
Number of operating segments									6
Maximum [Member] | Sales Revenue, Net [Member] | Largest Customer [Member] | Customer Concentration Risk [Member]
Segment Reporting Information [Line Items]
Percentage of total sales of largest customer, less than									1.00%
Maximum [Member] | Foreign [Member]
Segment Reporting Information [Line Items]
Sales, percentage of total									2.00%	2.00%	2.00%
Long-lived assets, percentage of total, less than	5.00%				5.00%				5.00%	5.00%	5.00%

Summary by Business Segment (Fi

Summary by Business Segment (Financial Information by Segment) (Details) - USD ($) $ in Thousands		3 Months Ended												12 Months Ended
		Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Net sales		$ 1,294,084		$ 1,295,414		$ 1,374,569		$ 1,349,710		$ 1,301,723	$ 1,331,820	$ 1,357,755	$ 1,313,587	$ 5,313,777	$ 5,304,885	$ 5,072,537
Cost of products sold (excluding depreciation)														2,301,598	2,355,875	2,247,574
Selling, distribution and administrative expenses														2,042,754	1,978,674	1,889,123
Merger costs and other special charges														35,967	0	0
Depreciation														318,552	297,710	275,461
Amortization														34,195	31,348	29,845
Total costs and expenses														4,733,066	4,663,607	4,442,003
Operating income		132,401	[1]	$ 125,587	[1]	$ 170,145	[1]	$ 152,578	[1]	147,530	$ 162,886	$ 175,781	$ 155,081	580,711	641,278	630,534
Assets		6,134,956								5,973,610				6,134,956	5,973,610	5,793,314
Capital expenditures														456,899	468,789	354,587
Gas and Rent [Member]
Segment Reporting Information [Line Items]
Net sales														3,459,502	3,351,019	3,226,822
Hardgoods [Member]
Segment Reporting Information [Line Items]
Net sales														1,854,275	1,953,866	1,845,715
Operating Segments [Member] | Distribution Business Segment [Member]
Segment Reporting Information [Line Items]
Net sales														4,716,228	4,773,489	4,558,790
Cost of products sold (excluding depreciation)														2,037,492	2,092,466	1,996,065
Selling, distribution and administrative expenses														1,828,814	1,792,116	1,705,408
Merger costs and other special charges														0
Depreciation														288,704	272,200	252,329
Amortization														29,403	27,373	25,512
Total costs and expenses														4,184,413	4,184,155	3,979,314
Operating income														531,815	589,334	579,476
Assets		5,531,042								5,397,535				5,531,042	5,397,535	5,222,781
Capital expenditures														426,290	438,867	317,066
Operating Segments [Member] | Distribution Business Segment [Member] | Gas and Rent [Member]
Segment Reporting Information [Line Items]
Net sales														2,866,065	2,823,297	2,717,272
Operating Segments [Member] | Distribution Business Segment [Member] | Hardgoods [Member]
Segment Reporting Information [Line Items]
Net sales														1,850,163	1,950,192	1,841,518
Operating Segments [Member] | All Other Operations Business Segment [Member]
Segment Reporting Information [Line Items]
Net sales														635,769	560,622	544,154
Cost of products sold (excluding depreciation)														302,326	292,635	281,916
Selling, distribution and administrative expenses														213,940	186,558	176,289
Merger costs and other special charges														0
Depreciation														29,848	25,510	23,132
Amortization														4,792	3,975	4,333
Total costs and expenses														550,906	508,678	485,670
Operating income														84,863	51,944	58,484
Assets		603,914								576,075				603,914	576,075	570,533
Capital expenditures														30,609	29,922	37,521
Operating Segments [Member] | All Other Operations Business Segment [Member] | Gas and Rent [Member]
Segment Reporting Information [Line Items]
Net sales														631,646	556,941	539,954
Operating Segments [Member] | All Other Operations Business Segment [Member] | Hardgoods [Member]
Segment Reporting Information [Line Items]
Net sales														4,123	3,681	4,200
Eliminations and Other [Member]
Segment Reporting Information [Line Items]
Net sales	[2]													(38,220)	(29,226)	(30,407)
Cost of products sold (excluding depreciation)	[2]													(38,220)	(29,226)	(30,407)
Selling, distribution and administrative expenses														0	0	7,426
Merger costs and other special charges														35,967
Depreciation														0	0	0
Amortization														0	0	0
Total costs and expenses														(2,253)	(29,226)	(22,981)
Operating income														(35,967)	0	(7,426)
Assets		$ 0								$ 0				0	0	0
Capital expenditures														0	0	0
Eliminations and Other [Member] | Gas and Rent [Member]
Segment Reporting Information [Line Items]
Net sales														(38,209)	(29,219)	(30,404)
Eliminations and Other [Member] | Hardgoods [Member]
Segment Reporting Information [Line Items]
Net sales														$ (11)	$ (7)	$ (3)
[1]	Operating income includes the following items:(In thousands)First Second Third Fourth2016 Merger costs (Note 2)$— $— $21,393 $7,574Special charges (Note 18)— — — 7,000
[2]	Amounts in the “Eliminations and Other” column represent the elimination of intercompany sales and associated gross profit on sales from the Company’s All Other Operations business segment to its Distribution business segment.

Supplementary Information (U114

Supplementary Information (Unaudited) (Summary of Unaudited Results of Operations) (Details) - USD ($) $ / shares in Units, $ in Thousands	Mar. 31, 2016	Mar. 31, 2016		Dec. 31, 2015		Sep. 30, 2015		Jun. 30, 2015		Mar. 31, 2015		Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Selected Quarterly Financial Information [Abstract]
Net sales		$ 1,294,084		$ 1,295,414		$ 1,374,569		$ 1,349,710		$ 1,301,723		$ 1,331,820		$ 1,357,755		$ 1,313,587		$ 5,313,777	$ 5,304,885	$ 5,072,537
Operating income		$ 132,401	[1]	$ 125,587	[1]	$ 170,145	[1]	$ 152,578	[1]	$ 147,530		$ 162,886		$ 175,781		$ 155,081		$ 580,711	$ 641,278	$ 630,534
Basic earnings per share		$ 1.07	[2]	$ 1.02	[2]	$ 1.33	[2]	$ 1.17	[2]	$ 1.17	[2]	$ 1.25	[2]	$ 1.32	[2]	$ 1.20	[2]	$ 4.60	$ 4.93	$ 4.76
Diluted earnings per share		$ 1.05	[2]	$ 1.01	[2]	$ 1.31	[2]	$ 1.16	[2]	$ 1.15	[2]	$ 1.23	[2]	$ 1.30	[2]	$ 1.18	[2]	$ 4.54	$ 4.85	$ 4.68
Merger costs		$ 7,574		$ 21,393		$ 0		$ 0										$ 28,967
Special charges	$ 7,000	$ 7,000		$ 0		$ 0		$ 0
[1]	Operating income includes the following items:(In thousands)First Second Third Fourth2016 Merger costs (Note 2)$— $— $21,393 $7,574Special charges (Note 18)— — — 7,000
[2]	Earnings per share calculations for each of the quarters are based on the weighted average number of shares outstanding in each quarter. Therefore, the sum of the quarterly earnings per share does not necessarily equal the full year earnings per share disclosed on the consolidated statements of earnings.

Subsequent Events (Details)

Subsequent Events (Details) - USD ($)		May. 15, 2016	May. 09, 2016	Apr. 15, 2016	Mar. 31, 2016	Mar. 31, 2015
Senior notes, net [Member]
Subsequent Event [Line Items]
Debt instrument, face amount					$ 1,800,000,000	$ 1,650,000,000
Senior notes, net [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt instrument, redemption price, percentage		100.00%
2.95% senior notes due June 2016 [Member] | Senior notes, net [Member]
Subsequent Event [Line Items]
Debt instrument, face amount	[1]					$ 250,000,000
2.95% senior notes due June 2016 [Member] | Senior notes, net [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt instrument, face amount	[1]			$ 250,000,000
Debt instrument, interest rate, stated percentage	[1]			2.95%
Affected Notes [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt instrument, face amount			$ 1,000
Cash payment per $1000 par value of affected senior notes for consent solicitation			$ 1.50
[1]	The 2016 Notes are included within the “Current portion of long-term debt” line item on the Company’s consolidated balance sheet based on the maturity date.

Valuation and Qualifying Acc116

Valuation and Qualifying Accounts (Schedule of Valuation and Qualifying Accounts) (Details) - Accounts Receivable - Allowances for Doubtful Accounts [Member] - USD ($) $ in Thousands		12 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period		$ 27,016	$ 31,757	$ 28,650
Additions charged to costs and expenses		16,680	15,843	20,310
Additions charged to other accounts	[1]	4,349	3,228	7,163
Deductions	[2]	(21,086)	(23,812)	(24,366)
Balance at end of period		$ 26,959	$ 27,016	$ 31,757
[1]	Principally reflects subsequent collections of accounts previously written-off.
[2]	Write-off of uncollectible accounts.