Tidewater (TDW) 10-K28 May 152015 FY Annual reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information (USD $)	12 Months Ended
Document and Entity Information (USD $)	Mar. 31, 2015	Apr. 30, 2015	Sep. 30, 2014
Document Information [Line Items]
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Trading Symbol	TDW
Entity Registrant Name	TIDEWATER INC
Entity Central Index Key	98222
Current Fiscal Year End Date	-28
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		47,029,359
Entity Public Float			$1,924,107,380

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Current assets:
Cash and cash equivalents	$78,568	$60,359
Trade and other receivables, less allowance for doubtful accounts of $37,634 in 2015 and $35,737 in 2014	303,096	252,421
Due from affiliate	420,365	429,450
Marine operating supplies	49,005	57,392
Other current assets	17,781	20,587
Total current assets	868,815	820,209
Investments in, at equity, and advances to unconsolidated companies	65,844	63,928
Properties and equipment:
Vessels and related equipment	4,717,132	4,521,102
Other properties and equipment	119,879	97,714
Properties and equipment, gross	4,837,011	4,618,816
Less accumulated depreciation and amortization	1,090,704	997,208
Net properties and equipment	3,746,307	3,621,608
Goodwill		283,699	[1],[2]
Other assets	75,196	96,385
Total assets	4,756,162	4,885,829
LIABILITIES AND EQUITY
Accrued property and liability losses	3,669	3,631
Current liabilities:
Accounts payable	54,011	74,515
Accrued expenses	146,255	157,302
Due to affiliate	185,657	86,154
Accrued property and liability losses	3,669	3,631
Current portion of long-term debt	10,181	9,512
Other current liabilities	82,461	70,567
Total current liabilities	482,234	401,681
Long-term debt	1,524,295	1,505,358
Deferred income taxes	23,276	108,929
Other liabilities and deferred credits	235,108	179,204
Commitments and Contingencies (Note 12)
Equity:
Common stock of $0.10 par value, 125,000,000 shares authorized, issued 47,029,359 shares at March 31, 2015 and 49,730,442 shares at March 31, 2014	4,703	4,973
Additional paid-in capital	159,940	142,381
Retained earnings	2,330,223	2,544,255
Accumulated other comprehensive loss	-20,378	-12,225
Total stockholders' equity	2,474,488	2,679,384
Noncontrolling interests	6,227	5,987
Total equity	2,480,715	2,685,371
Total liabilities and equity	4,756,162	4,885,829
Noncurrent Liabilities
LIABILITIES AND EQUITY
Accrued property and liability losses	10,534	5,286
Current liabilities:
Accrued property and liability losses	$10,534	$5,286

[1]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
[2]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Allowance for doubtful accounts	$37,634	$35,737
Common stock, par value	$0.10	$0.10
Common stock, shares authorized	125,000,000	125,000,000
Common stock, issued	47,029,359	49,730,442

Consolidated_Statements_of_Ear

Consolidated Statements of Earnings (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014	Mar. 31, 2013
Revenues:
Vessel revenues	$1,468,358		$1,418,461	$1,229,998
Other operating revenues	27,159		16,642	14,167
Total revenues	1,495,517		1,435,103	1,244,165
Costs and expenses:
Vessel operating costs	834,368		795,890	692,581
Costs of other operating revenues	26,505		15,745	12,216
General and administrative	189,819		187,976	175,609
Vessel operating leases	28,322		21,910	16,837
Depreciation and amortization	175,204		167,480	147,299
Gain on asset dispositions, net	-9,271		-11,722	-6,609
Goodwill impairment	283,699	[1]	56,283
Restructuring charge	4,052
Total costs and expenses	1,532,698		1,233,562	1,037,933
Operating income (loss)	-37,181		201,541	206,232
Other income (expenses):
Foreign exchange gain	8,678		1,541	3,011
Equity in net earnings of unconsolidated companies	10,179		15,801	12,189
Interest income and other, net	1,927		2,123	3,476
Loss on early extinguishment of debt			-4,144
Interest and other debt costs, net	-50,029		-43,814	-29,745
Total other income (expenses)	-29,245		-28,493	-11,069
Earnings (loss) before income taxes	-66,426		173,048	195,163
Income tax (benefit) expense	-1,077		32,793	44,413
Net earnings (loss)	-65,349		140,255	150,750
Less: Net loss attributable to noncontrolling interests	-159
Net earnings (loss) attributable to Tidewater Inc.	($65,190)		$140,255	$150,750
Basic (loss) earnings per common share	($1.34)		$2.84	$3.04
Diluted (loss) earnings per common share	($1.34)		$2.82	$3.03
Weighted average common shares outstanding	48,658,840		49,392,749	49,550,391
Dilutive effect of stock options and restricted stock			287,365	183,649
Adjusted weighted average common shares	48,658,840		49,680,114	49,734,040

[1]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Net (loss) earnings	($65,349)	$140,255	$150,750
Other comprehensive income (loss):
Unrealized gains (losses) on available for sale securities, net of tax of $0, $115 and ($200), respectively	143	213	-372
Amortization of loss on derivative contract, net of tax of $0, $251 and $251, respectively	717	466	466
Change in supplemental executive retirement plan pension liability, net of tax of $0, $409 and $1,306 respectively	-1,845	760	2,427
Change in pension plan minimum liability, net of tax of $0, $763 and ($290), respectively	-5,739	1,417	-539
Change in other benefit plan minimum liability, net of tax of $(769), $1,109 and $111, respectively	-1,429	2,060	207
Total comprehensive (loss) income	($73,502)	$145,171	$152,939

Consolidated_Statements_of_Com1

Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Unrealized gains/(losses) on available-for-sale securities, tax	$0	$115	($200)
Amortization of loss on derivative contract, tax	0	251	251
Change in supplemental executive retirement plan pension liability, tax	0	409	1,306
Change in Pension Plan minimum liability, tax	0	763	-290
Change in Other Benefit Plan minimum liability, tax	($769)	$1,109	$111

Consolidated_Statements_of_Equ

Consolidated Statements of Equity (USD $)	Total	Common stock	Additional paid- in capital	Retained earnings	Accumulated other comprehensive loss	Non controlling interest
In Thousands	Total	Common stock	Additional paid- in capital	Retained earnings	Accumulated other comprehensive loss	Non controlling interest
Balance at Mar. 31, 2012	$2,526,357	$5,125	$102,726	$2,437,836	($19,330)
Total comprehensive income	152,939			150,750	2,189
Stock option activity	6,145	14	6,131
Cash dividends declared ($1.00 per share)	-49,766			-49,766
Retirement of common stock	-85,034	-187		-84,847
Amortization of restricted stock units	6,711	6	6,705
Amortization/cancellation of restricted stock	4,404	-9	4,413
Balance at Mar. 31, 2013	2,561,756	4,949	119,975	2,453,973	-17,141
Total comprehensive income	145,171			140,255	4,916
Stock option activity	9,465	20	9,445
Cash dividends declared ($1.00 per share)	-49,973			-49,973
Amortization of restricted stock units	9,933	10	9,923
Amortization/cancellation of restricted stock	3,032	-6	3,038
Noncontrolling interests	5,987					5,987
Balance at Mar. 31, 2014	2,685,371	4,973	142,381	2,544,255	-12,225	5,987
Total comprehensive income	-73,502			-65,190	-8,153	-159
Stock option activity	-688	3	-691
Cash dividends declared ($1.00 per share)	-49,127			-49,127
Retirement of common stock	-99,999	-284		-99,715
Amortization of restricted stock units	15,287	17	15,270
Amortization/cancellation of restricted stock	2,974	-6	2,980
Cash received from non-controlling interests, net	399					399
Balance at Mar. 31, 2015	$2,480,715	$4,703	$159,940	$2,330,223	($20,378)	$6,227

Consolidated_Statements_of_Equ1

Consolidated Statements of Equity (Parenthetical) (USD $)	12 Months Ended
Consolidated Statements of Equity (Parenthetical) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Cash dividends, per share declared	$1	$1	$1

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014	Mar. 31, 2013
Operating activities:
Net (loss) earnings	($65,349)		$140,255	$150,750
Adjustments to reconcile net (loss) earnings to net cash provided by operating activities:
Depreciation and amortization	175,204		167,480	147,299
Benefit for deferred income taxes	-72,389		-34,709	-11,733
Gain on asset dispositions, net	-9,271		-11,722	-6,609
Goodwill impairment	283,699	[1]	56,283
Equity in earnings of unconsolidated companies, net of dividends	-1,916		-15,801	30
Compensation expense - stock based	21,374		19,642	19,416
Excess tax (benefit) liability on stock options exercised	1,784		-299	-278
Changes in assets and liabilities, net:
Trade and other receivables	-43,537		13,485	-38,438
Changes in due to/from affiliate, net	108,588		-260,675	-56,077
Marine operating supplies	6,148		5,715	-8,498
Other current assets	2,794		-7,600	-1,663
Accounts payable	-22,989		-1,395	-5,888
Accrued expenses	-11,435		34,458	9,098
Accrued property and liability losses	38		-429	497
Other current liabilities	118		10,373	4,846
Other liabilities and deferred credits	4,875		-11,842	822
Other, net	-19,023		1,398	10,349
Net cash provided by operating activities	358,713		104,617	213,923
Cash flows from investing activities:
Proceeds from sales of assets	8,310		51,330	27,278
Proceeds from sale/leaseback of assets	123,950		270,575
Additions to properties and equipment	-364,194		-594,695	-440,572
Payments for acquisition, net of cash acquired			-127,737
Other	516		-3,158	-193
Net cash used in investing activities	-231,418		-403,685	-413,487
Cash flows from financing activities:
Debt issuance costs	-556		-5,347	-51
Principal payments on long-term debt	-97,823		-1,103,054	-60,000
Debt borrowings	138,488		1,465,362	110,000
Proceeds from exercise of stock options	1,023		6,863	3,818
Cash dividends	-48,834		-49,816	-49,588
Excess tax benefit (liability) on stock options exercised	-1,784		299	278
Cash contributions from noncontrolling interests, net	399		4,551
Repurchases of common stock	-99,999			-85,034
Net cash (used in) provided by financing activities	-109,086		318,858	-80,577
Net change in cash and cash equivalents	18,209		19,790	-280,141
Cash and cash equivalents at beginning of year	60,359		40,569	320,710
Cash and cash equivalents at end of year	78,568		60,359	40,569
Cash paid during the year for:
Interest, net of amounts capitalized	49,390		34,190	27,443
Income taxes	74,310		59,266	54,722
Supplemental disclosure of noncash investing activities:
Additions to properties and equipment	$2,068		$5,751	$12,010

[1]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.

Nature_of_Operations_and_Summa

Nature of Operations and Summary of Significant Accounting Policies

12 Months Ended

Mar. 31, 2015

Nature of Operations and Summary of Significant Accounting Policies

-1

NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Nature of Operations

The company provides offshore service vessels and marine support services to the global offshore energy industry through the operation of a diversified fleet of offshore marine service vessels. The company’s revenues, net earnings and cash flows from operations are dependent upon the activity level of the vessel fleet. Like other energy service companies, the level of the company’s business activity is driven by the level of drilling and exploration activity by our customers. Our customers’ activity, in turn, is dependent on crude oil and natural gas prices, which fluctuate depending on respective levels of supply and demand for crude oil and natural gas.

Principles of Consolidation

The consolidated financial statements include the accounts of Tidewater Inc. and its subsidiaries. Intercompany balances and transactions are eliminated in consolidation.

Use of Estimates in Preparation of Financial Statements

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. The accompanying consolidated financial statements include estimates for allowance for doubtful accounts, useful lives of property and equipment, valuation of goodwill, income tax provisions, impairments, commitments and contingencies and certain accrued liabilities. We evaluate our estimates and assumptions on an ongoing basis based on a combination of historical information and various other assumptions that are considered reasonable under the particular circumstances, the results of which form the basis for making judgments about carrying values of assets and liabilities that are not readily apparent from other sources. These accounting policies involve judgment and uncertainties to such an extent that there is reasonable likelihood that materially different amounts could have been reported under different conditions or if different assumptions had been used, as such, actual results may differ from these estimates.

Cash Equivalents

The company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents.

Marine Operating Supplies

Marine operating supplies, which consist primarily of operating parts and supplies for the company’s vessels, are stated at the lower of weighted-average cost or market.

Properties and Equipment

Depreciation and Amortization

Properties and equipment are stated at cost. Depreciation is computed primarily on the straight-line basis beginning with the date construction is completed, with salvage values of 5%-10% for marine equipment, using estimated useful lives of 15 - 25 years for marine equipment (from date of construction) and 3 - 30 years for other properties and equipment. Depreciation is provided for all vessels unless a vessel meets the criteria to be classified as held for sale. Estimated remaining useful lives are reviewed when there has been a change in circumstances that indicates the original estimated useful life may no longer be appropriate. Upon retirement or disposal of a fixed asset, the costs and related accumulated depreciation are removed from the respective accounts and any gains or losses are included in our consolidated statements of earnings. Used equipment is depreciated in accordance with this above policy; however, no life less than six years is used for marine equipment regardless of the date constructed.

Maintenance and Repairs

Maintenance and repairs (including major repair costs) are expensed as incurred during the asset’s original estimated useful life (its original depreciable life). Major repair costs incurred after the original estimated depreciable life that also have the effect of extending the useful life (for example, the complete overhaul of main engines, the replacement of mechanical components, or the replacement of steel in the vessel’s hull) of the asset are capitalized and amortized over 30 months. Vessel modifications that are performed for a specific customer contract are capitalized and amortized over the firm contract term. Major modifications to equipment that are being performed not only for a specific customer contract are capitalized and amortized over the remaining life of the equipment. The majority of the company’s vessels require certification inspections twice in every five year period, and the company schedules major repairs and maintenance, including time the vessel will be in a dry dock, when it is anticipated that the work can be performed. While the actual length of time between major repairs and maintenance and drydockings can vary, in the case of major repairs incurred after a vessel’s original estimated useful life, we use a 30 month amortization period for depreciating the capitalized costs of these major repairs and maintenance and drydockings.

Net Properties and Equipment

The following is a summary of net properties and equipment at March 31:

2015

2014

Number

Carrying

Number

Carrying

Of Vessels

Value

Of Vessels

Value

(In thousands)

Owned vessels in active service

242

3,310,476

257

3,281,391

Stacked vessels

38,489

9,743

Marine equipment and other assets under construction

315,552

268,189

Other property and equipment (A)

81,790

62,285

Totals

263

3,746,307

272

3,621,608

(A)

Other property and equipment includes six remotely operated vehicles the company took delivery of in fiscal 2014 and two remotely operated vehicles the company took delivery of in fiscal 2015.

The company considers a vessel to be stacked if the vessel crew is disembarked and limited maintenance is being performed on the vessel. The company reduces operating costs by stacking vessels when management does not foresee opportunities to profitably or strategically operate the vessels in the near future. Vessels are added to this list when market conditions warrant and they are removed from this list when they are returned to active service, sold or otherwise disposed. When economically practical marketing opportunities arise, the stacked vessels can be returned to service by performing any necessary maintenance on the vessel and returning fleet personnel to operate the vessel. Although not currently fulfilling charters, stacked vessels are considered to be in service and are included in the calculation of the company’s utilization statistics. Stacked vessels at March 31, 2015 and 2014 have an average age of 20.7 and 32.2 years, respectively.

All vessels are classified in the company’s consolidated balance sheets in Properties and Equipment. No vessels are classified as held for sale because no vessel meets the criteria. Stacked vessels and vessels withdrawn from service are reviewed for impairment semiannually or whenever changes in circumstances indicate that the carrying amount of a vessel may not be recoverable.

Impairment of Long-Lived Assets

The company reviews the vessels in its active fleet for impairment whenever events occur or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. In such evaluation, the estimated future undiscounted cash flows generated by an asset group are compared with the carrying amount of the asset group to determine if a write-down may be required. With respect to vessels that have not been stacked, we group together for impairment testing purposes vessels with similar operating and marketing characteristics. We also subdivide our groupings of assets with similar operating and marketing characteristics between our older vessels and newer vessels.

The company estimates cash flows based upon historical data adjusted for the company’s best estimate of expected future market performance, which, in turn, is based on industry trends. If an asset group fails the undiscounted cash flow test, the company uses the discounted cash flow method to determine the estimated fair value of each asset group and compares such estimated fair value (considered Level 3), as defined by Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 360 Impairment or Disposal of Long-lived Assets, to the carrying value of each asset group in order to determine if impairment exists. If impairment exists, the carrying value of the asset group is reduced to its estimated fair value.

The primary estimates and assumptions used in reviewing active vessel groups for impairment include utilization rates, average dayrates, and average daily operating expenses. These estimates are made based on recent actual trends in utilization, dayrates and operating costs and reflect management’s best estimate of expected market conditions during the period of future cash flows. These assumptions and estimates have changed considerably as market conditions have changed and they are reasonably likely to continue to change as market conditions change in the future. Although the company believes its assumptions and estimates are reasonable, deviations from the assumptions and estimates could produce materially different results. Management estimates may vary considerably from actual outcomes due to future adverse market conditions or poor operating results that could result in the inability to recover the current carrying value of an asset group, thereby possibly requiring an impairment charge in the future. As the company’s fleet continues to age, management closely monitors the estimates and assumptions used in the impairment analysis in order to properly identify evolving trends and changes in market conditions that could impact the results of the impairment evaluation.

In addition to the periodic review of its active long-lived assets for impairment when circumstances warrant, the company also performs a review of its stacked vessels and vessels withdrawn from service every six months or whenever changes in circumstances indicate that the carrying amount of a vessel may not be recoverable. Management estimates each stacked vessel’s fair value by considering items such as the vessel’s age, length of time stacked, likelihood of a return to active service, actual recent sales of similar vessels, among others. In certain situations we obtain an estimate of the fair value of the stacked vessel from third-party appraisers or brokers. The company records an impairment charge when the carrying value of a vessel withdrawn from service or a stacked vessel exceeds its estimated fair value. The estimates of fair value of stacked vessels are also subject to significant variability, are sensitive to changes in market conditions, and are reasonably likely to change in the future. The company has consistently recorded modest gains on the sale of stacked vessels. Refer to Note (13) for a discussion on asset impairments.

Goodwill

Goodwill represents the cost in excess of fair value of the net assets of companies acquired. Goodwill primarily relates to the fiscal 1998 acquisition of O.I.L. Ltd. and the fiscal 2014 acquisition of Troms Offshore. The company tests goodwill for impairment annually at the reporting unit level using carrying amounts as of December 31 or more frequently if events and circumstances indicate that goodwill might be impaired. The company has the option of assessing qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit exceeds its carrying amount. In the event that a qualitative assessment indicates that the fair value of a reporting unit exceeds its carrying value the two step impairment test is not necessary. If, however, the assessment of qualitative factors indicates otherwise, the standard two-step method for evaluating goodwill for impairment as prescribed by Financial Accounting Standards Board (FASB) Accounting Standards Codification (ASC) 350, Intangibles-Goodwill and Other must be performed. Step one involves comparing the fair value of the reporting unit to its carrying amount. If the fair value of the reporting unit is greater than its carrying amount, there is no impairment. If the reporting unit’s carrying amount is greater than the fair value, the second step must be completed to measure the amount of impairment, if any. Step two involves calculating the implied fair value of goodwill by deducting the fair value of all tangible and intangible assets, excluding goodwill, of the reporting unit from the fair value of the reporting unit as determined in step one. The implied fair value of goodwill determined in this step is compared to the carrying value of goodwill. If the implied fair value of goodwill is less than the carrying value of goodwill, an impairment loss is recognized equal to the difference.

The company performed its annual goodwill impairment assessment as of December 31, 2014 and 2013 and recorded goodwill impairment charges of $283.7 million and $56.3 million, respectively. The December 31, 2014 impairment charge was due to the likely negative effect on average day rates and utilization levels of the company’s vessels as a result of the rapid and significant decline in crude oil and natural gas prices which occurred and accelerated throughout the latter part of the company’s third quarter of fiscal 2015. The December 31, 2013 impairment charge related to the company’s Asia/Pacific segment. During the quarter ended June 30, 2013, $42.2 million of goodwill related to the acquisition of Troms Offshore was allocated to the Sub-Saharan Africa/Europe segment. Refer to Note (16) for a complete discussion of Goodwill.

Accrued Property and Liability Losses

The company’s insurance subsidiary establishes case-based reserves for estimates of reported losses on direct business written, estimates received from ceding reinsurers, and reserves based on past experience of unreported losses. Such losses principally relate to the company’s vessel operations and are included as a component of vessel operating costs in the consolidated statements of earnings. The liability for such losses and the related reimbursement receivable from reinsurance companies are classified in the consolidated balance sheets into current and noncurrent amounts based upon estimates of when the liabilities will be settled and when the receivables will be collected.

The following table discloses the total amount of current and long-term liabilities related to accrued property and liability losses not subject to reinsurance recoverability, but considered currently payable as of March 31:

(In thousands)

2015

2014

Accrued property and liability losses

14,203

8,917

Pension and Other Postretirement Benefits

The company follows the provisions of ASC 715, Compensation – Retirement Benefits, and uses a March 31 measurement date for determining net periodic benefit costs, benefit obligations and the fair value of plan assets. Net periodic pension costs and accumulated benefit obligations are determined using a number of assumptions including the discount rates used to measure future obligations and expenses, the rate of compensation increases, retirement ages, mortality rates, expected long-term return on plan assets, health care cost trends, and other assumptions, all of which have a significant impact on the amounts reported.

The company’s pension cost consists of service costs, interest costs, expected returns on plan assets, amortization of prior service costs or benefits and actuarial gains and losses. The company considers a number of factors in developing its pension assumptions, including an evaluation of relevant discount rates, expected long-term returns on plan assets, plan asset allocations, expected changes in wages and retirement benefits, analyses of current market conditions and input from actuaries and other consultants.

Net periodic benefit costs are based on a market-related valuation of assets equal to the fair value of assets. For the long-term rate of return, assumptions are developed regarding the expected rate of return on plan assets based on historical experience and projected long-term investment returns, which consider the plan’s target asset allocation and long-term asset class return expectations. Assumptions for the discount rate use the equivalent single discount rate based on discounting expected plan benefit cash flows using the Mercer Bond Index Curve. For the projected compensation trend rate, short-term and long-term compensation expectations for participants, including salary increases and performance bonus payments are considered. For the health care cost trend rate for other postretirement benefits, assumptions are established for health care cost trends, applying an initial trend rate that reflects recent historical experience and broader national statistics with an ultimate trend rate that assumes that the portion of gross domestic product devoted to health care eventually becomes constant. Refer to Note (6) for a complete discussion on compensation – retirement benefits.

Income Taxes

Income taxes are accounted for in accordance with the provisions of ASC 740, Income Taxes. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. 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 are expected to be recovered or settled. 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. Deferred taxes are not provided on undistributed earnings of certain non-U.S. subsidiaries and business ventures because the company considers those earnings to be permanently invested abroad. Refer to Note (4) for a complete discussion on income taxes.

Revenue Recognition

The company’s primary source of revenue is derived from time charter contracts of its vessels on a rate per day of service basis; therefore, vessel revenues are recognized on a daily basis throughout the contract period. These vessel time charter contracts are generally either on a term basis (average three months to three years) or on a “spot” basis. The base rate of hire for a term contract is generally a fixed rate, provided, however, that term contracts at times include escalation clauses to recover specific additional costs. A spot contract is a short-term agreement to provide offshore marine services to a customer for a specific short-term job. Spot contract terms generally range from one day to three months. Vessel revenues are recognized on a daily basis throughout the contract period. There are no material differences in the cost structure of the company’s contracts based on whether the contracts are spot or term for the operating costs are generally the same without regard to the length of a contract.

Operating Costs

Vessel operating costs are incurred on a daily basis and consist primarily of costs such as crew wages; repair and maintenance; insurance and loss reserves; fuel, lube oil and supplies; and other vessel expenses, which include but are not limited to costs such as brokers’ commissions, training costs, agent fees, port fees, canal transit fees, temporary importation fees, vessel certification fees, and satellite communication fees. Repair and maintenance costs include both routine costs and major drydocking repair costs, which occur during the initial economic useful life of the vessel. Vessel operating costs are recognized as incurred on a daily basis.

Foreign Currency Translation

The U.S. dollar is the functional currency for all of the company’s existing international operations, as transactions in these operations are predominately denominated in U.S. dollars. Foreign currency exchange gains and losses from the revaluation of the company’s foreign currency denominated monetary assets and liabilities are included in the consolidated statements of earnings.

Earnings Per Share

The company follows ASC 260, Earnings Per Share and reports both basic earnings per share and diluted earnings per share. The calculation of basic earnings per share is computed based on the weighted average number of shares of common stock outstanding. Dilutive earnings per share is computed based on the weighted average number of shares of common stock plus the effect of dilutive potential common shares outstanding during the period using the treasury stock method. Diluted earnings per share includes the dilutive effect of stock options and restricted stock grants (both time and performance based) awarded as part of the company’s share-based compensation and incentive plans. Per share amounts disclosed in these Notes to Consolidated Financial Statements, unless otherwise indicated, are on a diluted basis. Refer to Note (10), Earnings Per Share.

Concentrations of Credit Risk

The company’s financial instruments that are exposed to concentrations of credit risk consist primarily of trade and other receivables from a variety of domestic, international and national energy companies, including reinsurance companies for recoverable insurance losses. The company manages its exposure to risk by performing ongoing credit evaluations of its customers’ financial condition and generally does not require collateral. The company maintains an allowance for doubtful accounts for potential losses based on expected collectability and does not believe it is generally exposed to concentrations of credit risk that are likely to have a material adverse impact on the company’s financial position, results of operations, or cash flows.

Stock-Based Compensation

The company follows ASC 718, Compensation – Stock Compensation, for the expensing of stock options and other share-based payments. This topic requires that stock-based compensation transactions be accounted for using a fair-value-based method. The company uses the Black-Scholes option-pricing model to determine the fair-value of stock-based awards. Refer to Note (8) for a complete discussion on stock-based compensation.

Comprehensive Income

The company reports total comprehensive income and its components in the financial statements in accordance with ASC 220, Comprehensive Income. Total comprehensive income represents the net change in stockholders’ equity during a period from sources other than transactions with stockholders and, as such, includes net earnings. For the company, accumulated other comprehensive income is comprised of unrealized gains and losses on available-for-sale securities and derivative financial instruments, currency translation adjustment and any minimum pension liability for the company’s U.S. Defined Benefits Pension Plan and Supplemental Executive Retirement Plan. Refer to Note (9) for a complete discussion on comprehensive income.

Derivative Instruments and Hedging Activities

The company periodically utilizes derivative financial instruments to hedge against foreign currency denominated assets and liabilities and currency commitments. These transactions generally include forward currency contracts or interest rate swaps that are entered into with major financial institutions. Derivative financial instruments are intended to reduce the company’s exposure to foreign currency exchange risk and interest rate risk.

The company records derivative financial instruments in its consolidated balance sheets at fair value as either assets or liabilities. The accounting for changes in the fair value of a derivative instrument depends on the intended use of the derivative and the resulting designation, which is established at the inception of a derivative. The company formally documents, at the inception of a hedge, the hedging relationship and the entity’s risk management objective and strategy for undertaking the hedge, including identification of the hedging instrument, the hedged item or transaction, the nature of the risk being hedged, the method used to assess effectiveness and the method that will be used to measure hedge ineffectiveness of derivative instruments that receive hedge accounting treatment.

For derivative instruments designated as foreign currency or interest rate hedges (cash flow hedge), changes in fair value, to the extent the hedge is effective, are recognized in other comprehensive income until the hedged item is recognized in earnings. Hedge effectiveness is assessed quarterly based on the total change in the derivative’s fair value. Amounts representing hedge ineffectiveness are recorded in earnings. Any change in fair value of derivative financial instruments that are speculative in nature and do not qualify for hedge accounting treatment is also recognized immediately in earnings. Proceeds received upon termination of derivative financial instruments qualifying as fair value hedges are deferred and amortized into income over the remaining life of the hedged item using the effective interest rate method.

Fair Value Measurements

The company follows the provisions of ASC 820, Fair Value Measurements and Disclosures, for financial assets and liabilities that are measured and reported at fair value on a recurring basis. ASC 820 establishes a hierarchy for inputs used in measuring fair value. Fair value is calculated based on assumptions that market participants would use in pricing assets and liabilities and not on assumptions specific to the entity. The statement requires that each asset and liability carried at fair value be classified into one of the following categories:

Level 1:

Quoted market prices in active markets for identical assets or liabilities

Level 2:

Observable market based inputs or unobservable inputs that are corroborated by market data

Level 3:

Unobservable inputs that are not corroborated by market data

Reclassifications

The company made certain reclassifications to prior period amounts to conform to the current year presentation. These reclassifications did not have a material effect on the consolidated statement of financial position, results of operations or cash flows.

Subsequent Events

The company evaluates subsequent events through the time of our filing on the date we issue financial statements.

Accounting Pronouncements

From time to time, new accounting pronouncements are issued by the FASB that are adopted by the company as of the specified effective date. Unless otherwise discussed, management believes that the impact of recently issued standards, which are not yet effective, will not have a material impact on the company’s consolidated financial statements upon adoption.

In May 2014, the FASB issued Accounting Standard Update (ASU) 2014-09 Revenue from Contracts with Customers. ASU 2014-09 supersedes prior revenue recognition guidance and provides a five step recognition framework that will require entities to recognize the amount of revenue to which it expects to be entitled for the transfer of goods and services. This new revenue recognition guidance is effective for the company in the first quarter of fiscal 2018 and may be implemented retrospectively to all years presented or in the period of adoption through a cumulative adjustment. The company believes that the impact of the implementation of this new guidance on its consolidated financial statements and disclosures will not be significant.

In August 2014, the FASB issued ASU 2014-15 Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. ASU 2014-15 requires management to assess the entity’s ability to continue as a going concern, and to provide related disclosures in certain circumstances. ASU 2014-15 is effective for annual and interim periods beginning after December 15, 2016. The company believes that the impact of the implementation of this new guidance on its consolidated financial statements and disclosures will not be significant.

ACQUISITION

ACQUISITION	12 Months Ended
ACQUISITION	Mar. 31, 2015
ACQUISITION	-2		ACQUISITION
	Troms Offshore Supply AS
	On June 4, 2013, the company, through a subsidiary, acquired Troms Offshore Supply AS, a Norwegian company (Troms Offshore). At the time of the acquisition, Troms Offshore owned four deepwater PSVs, and had two additional deepwater PSVs under construction, one delivered shortly after the acquisition and the other delivered in January 2014. The purchase price (not including transaction costs) consisted of a $150.0 million cash payment to the shareholders of Troms Offshore and the assumption of approximately $261.3 million of combined Troms Offshore obligations, comprised of net interest-bearing debt and the remaining installment payments due on vessels under construction. The company has performed a fair value analysis and the purchase price was allocated to the acquired assets and liabilities based on their fair values resulting in $42.2 million of goodwill, all of which was allocated to our Sub-Saharan Africa/Europe segment.
	The following table summarizes the allocation of the purchase price for the acquisition of Troms Offshore:


	(In thousands)
	Cash		$	22,263
	Trade receivables and other current assets			9,816
	Vessels (A)			245,605
	Goodwill (B)			42,160
	Payable and other liabilities			(13,020	)
	Notes payable			(156,824	)
	Total purchase price		$	150,000


	(A)	Includes $10.7 million in costs attributed to vessels under construction.
	(B)	Subsequently written off in December 2014.

	The effect of the acquisition on pro forma results of operations and the consolidated statement of operations for the years ended March 31, 2014 and 2013 are immaterial and therefore not presented.

Investment_in_Unconsolidated_C

Investment in Unconsolidated Companies	12 Months Ended
Investment in Unconsolidated Companies	Mar. 31, 2015
Investment in Unconsolidated Companies	-3	INVESTMENT IN UNCONSOLIDATED COMPANIES
	Investments in unconsolidated affiliates, generally 50% or less owned partnerships and corporations, are accounted for by the equity method. Under the equity method, the assets and liabilities of the unconsolidated joint venture companies are not consolidated in the company’s consolidated balance sheet.
	Investments in, at equity, and advances to unconsolidated joint venture companies at March 31, were as follows:


	(In thousands)		Percentage			2015	2014
	(In thousands)		Ownership			2015	2014
	Sonatide Marine, Ltd. (Angola)		49	%	$	63,893	62,126
	DTDW Holdings, Ltd. (Nigeria)		40	%		1,951	1,802
	Investments in, at equity, and advances to unconsolidated companies				$	65,844	63,928

	During the third quarter of fiscal 2014, the company advanced $1.9 million to a 40%-owned unconsolidated joint venture company located in Nigeria. The company also sold a vessel to this unconsolidated joint venture company for $23.3 million, and recognized a gain in the third quarter of fiscal 2014 of $7.9 million and a deferred gain of $5.2 million based on proportional ownership of the joint venture.

INCOME_TAXES

INCOME TAXES	12 Months Ended
INCOME TAXES	Mar. 31, 2015
INCOME TAXES	-4		INCOME TAXES

	We recognize deferred tax assets to the extent that we believe that these assets are more likely than not to be realized. In making such a determination, we consider all available positive and negative evidence, including future reversals of existing taxable temporary differences, projected future taxable income, tax-planning strategies, and results of recent operations. If we determine that we would be able to realize our deferred tax assets in the future in excess of their net recorded amount, we would make an adjustment to the deferred tax asset valuation allowance, which would reduce the provision for income taxes.

	We record uncertain tax positions in accordance with ASC 740 on the basis of a two-step process in which (1) we determine whether it is more likely than not that the tax positions will be sustained on the basis of the technical merits of the position and (2) for those tax positions that meet the more-likely-than-not recognition threshold, we recognize the largest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement with the related tax authority.

	Earnings before income taxes derived from United States and non-U.S. operations for the years ended March 31, are as follows:



	(In thousands)			2015			2014			2013
	Non-U.S.		$	(38,282	)		217,816			246,863
	United States			(27,985	)		(44,768	)		(51,700	)
			$	(66,267	)		173,048			195,163


	Income tax expense (benefit) for the years ended March 31, consists of the following:



				U.S.
	(In thousands)			Federal			State			International		Total
	2015
	Current		$	4,869			(9	)		66,452		71,312
	Deferred			(72,389	)		—			—		(72,389	)
			$	(67,520	)		(9	)		66,452		(1,077	)



	2014
	Current		$	(602	)		4			68,100		67,502
	Deferred			(34,226	)		—			(483	)	(34,709	)
			$	(34,828	)		4			67,617		32,793


	2013
	Current		$	(7,633	)		(313	)		64,092		56,146
	Deferred			(11,335	)		—			(398	)	(11,733	)
			$	(18,968	)		(313	)		63,694		44,413




	The actual income tax expense above differs from the amounts computed by applying the U.S. federal statutory tax rate of 35% to pre-tax earnings as a result of the following for the years ended March 31:



	(In thousands)			2015			2014			2013
	Computed “expected” tax expense		$	(23,193	)		60,567			68,307
	Increase (reduction) resulting from:
	Foreign income taxed at different rates			(13,570	)		(18,536	)		(23,965	)
	Foreign tax credits not previously recognized			—			(483	)		(398	)
	Expenses which are not deductible for tax purposes			472			720			498
	Non-deductible goodwill			15,811			2,941			—
	Reversal of basis difference – sale leaseback			—			(3,369	)		—
	Valuation allowance – deferred tax assets			17,829			(5,821	)		5,821
	Amortization of deferrals associated with intercompany sales to foreign tax jurisdictions			(2,358	)		(1,475	)		(6,232	)
	Expenses which are not deductible for book purposes			(832	)		(2,144	)		—
	Foreign taxes			5,688
	State taxes			(6	)		3			(203	)
	Other, net			(918	)		390			585
			$	(1,077	)		32,793			44,413


Income taxes resulting from intercompany vessel sales, as well as the tax effect of any reversing temporary differences resulting from the sales, are deferred and amortized on a straight-line basis over the remaining useful lives of the vessels.

The company is not liable for U.S. taxes on undistributed earnings of most of its non-U.S. subsidiaries and business ventures that it considers indefinitely reinvested abroad because the company adopted the provisions of the American Jobs Creation Act of 2004 (the Act) effective April 1, 2005. All previously recorded deferred tax assets and liabilities related to temporary differences, foreign tax credits, or prior undistributed earnings of these entities whose future and prior earnings were anticipated to be indefinitely reinvested abroad were reversed in March 2005.

The effective tax rate applicable to pre-tax earnings for the years ended March 31, is as follows:



			2015			2014			2013
Effective tax rate applicable to pre-tax earnings			1.63	%		18.95	%		22.76	%

The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at March 31, is as follows:



(In thousands)			2015			2014
Deferred tax assets:
Accrued employee benefit plan costs		$	21,874			21,423
Stock based compensation			8,731			7,162
Net operating loss and tax credit carryforwards			2,327			2,895
Other			3,901			2,896
Gross deferred tax assets			36,833			34,376
Less valuation allowance			(17,829	)		—
Net deferred tax assets			19,004			34,376
Deferred tax liabilities:
Depreciation and amortization			(19,004	)		(108,929	)
Gross deferred tax liabilities			(19,004	)		(108,929	)
Net deferred tax assets (liabilities)		$	—			(74,553	)


Management assesses the available positive and negative evidence to estimate whether sufficient future U.S. taxable income will be generated to permit use of the existing deferred tax assets. A significant piece of objective negative evidence evaluated was the cumulative loss for financial reporting purposes of domestic corporations that was incurred over the three-year period ended March 31, 2015. Such objective evidence limits the ability to consider other subjective evidence, such as our projections for future growth and tax planning strategies.

On the basis of this evaluation, as of March 31, 2015, a valuation allowance of $17,829 has been recorded against net deferred tax assets which are not more likely than not to be realized. The amount of the deferred tax asset considered realizable, however, could be adjusted if estimates of future U.S. taxable income during the carryforward period are reduced or increased or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as our projections for growth and/or tax planning strategies.

The company has not recognized a U.S. deferred tax liability associated with temporary differences related to investments in foreign subsidiaries that are essentially permanent in duration. The differences relate primarily to undistributed earnings and stock basis differences. Though the company does not anticipate repatriation of funds, a current U.S. tax liability would be recognized when the company receives those foreign funds in a taxable manner such as through receipt of dividends or sale of investments. A determination of the unrecognized deferred tax liability for temporary differences related to investments in foreign subsidiaries is not practicable due to uncertainty regarding the use of foreign tax credits which would become available as a result of a transaction.



The amount of foreign income that U.S. deferred taxes has not been recognized upon, as of March 31, is as follows:



(In thousands)			2015
Foreign income not recognized for U.S. deferred taxes		$	2,578,133

The company has the following foreign tax credit carry-forwards that expire in 2022.



(In thousands)			2015
Foreign tax credit carry-forwards		$	2,327

The company’s balance sheet reflects the following in accordance with ASC 740, Income Taxes at March 31:



(In thousands)			2015			2014
Tax liabilities for uncertain tax positions		$	16,305			18,008
Income tax payable			44,607			36,472

Included in the liability balances for uncertain tax positions above are $8.3 million of penalties and interest. The tax liabilities for uncertain tax positions are primarily attributable to a permanent establishment issue related to a foreign joint venture. Penalties and interest related to income tax liabilities are included in income tax expense. Income tax payable is included in other current liabilities.

Unrecognized tax benefits, which are not included in the liability for uncertain tax positions above as they have not been recognized in previous tax filings, and which would lower the effective tax rate if realized, at March 31, are as follows:



(In thousands)			2015
Unrecognized tax benefit related to state tax issues		$	11,685
Interest receivable on unrecognized tax benefit related to state tax issues			32

A reconciliation of the beginning and ending amount of all unrecognized tax benefits, including the unrecognized tax benefit related to state tax issues and the liability for uncertain tax positions (but excluding related penalties and interest) for the years ended March 31, are as follows:



(In thousands)			2015			2014			2013
Balance at April 1,		$	20,066			14,868			15,727
Additions based on tax positions related to the current year			1,342			4,393			2,041
Additions based on tax positions related to prior years			—			2,217			—
Reductions for tax positions of prior years			—			—			—
Exchange rate fluctuation			—			—			—
Settlement and lapse of statute of limitations			(1,710	)		(1,412	)		(2,900	)
Balance at March 31,		$	19,698			20,066			14,868


With limited exceptions, the company is no longer subject to tax audits by United States (U.S.) federal, state, local or foreign taxing authorities for years prior to 2007. The company has ongoing examinations by various state and foreign tax authorities and does not believe that the results of these examinations will have a material adverse effect on the company’s financial position or results of operations.

The company receives a tax benefit that is generated by certain employee stock benefit plan transactions. This benefit is recorded directly to additional paid-in-capital and does not reduce the company’s effective income tax rate. The tax benefit for the years ended March 31, are as follows:



(In thousands)			2015			2014			2013
Excess tax benefits on stock benefit transactions		$	(1,784	)		301			359

Indebtedness

Indebtedness	12 Months Ended
Indebtedness	Mar. 31, 2015
Indebtedness	-5		INDEBTEDNESS

	Revolving Credit and Term Loan Agreement

	In June 2013, the company amended and extended its existing credit facility. The amended credit agreement matures in June 2018 (the “Maturity Date”) and provides for a $900 million, five-year credit facility (“credit facility”) consisting of a (i) $600 million revolving credit facility (the “revolver”) and a (ii) $300 million term loan facility (“term loan”).

	Borrowings under the credit facility are unsecured and bear interest at the company’s option at (i) the greater of prime or the federal funds rate plus 0.25 to 1.00%, or (ii) Eurodollar rates, plus margins ranging from 1.25 to 2.00% based on the company’s consolidated funded debt to capitalization ratio. Commitment fees on the unused portion of the facilities range from 0.15 to 0.30% based on the company’s funded debt to total capitalization ratio. The credit facility requires that the company maintain a ratio of consolidated debt to consolidated total capitalization that does not exceed 55%, and maintain a consolidated interest coverage ratio (essentially consolidated earnings before interest, taxes, depreciation and amortization, or EBITDA, for the four prior fiscal quarters to consolidated interest charges, including capitalized interest, for such period) of not less than 3.0 to 1.0. All other terms, including the financial and negative covenants, are customary for facilities of its type and consistent with the prior agreement in all material respects.

	The company had $300 million in term loan borrowings and $20 million of revolver borrowings outstanding at March 31, 2015 (whose fair value approximates the carrying value because the borrowings bear interest at variable rates). The company had $580 million available under the revolver at March 31, 2015.

	Senior Debt Notes

	The determination of fair value includes an estimated credit spread between our long term debt and treasuries with similar matching expirations. The credit spread is determined based on comparable publicly traded companies in the oilfield service segment with similar credit ratings. These estimated fair values are based on Level 2 inputs.

	September 2013 Senior Notes

	On September 30, 2013, the company executed a note purchase agreement for $500 million and issued $300 million of senior unsecured notes to a group of institutional investors. The company issued the remaining $200 million of senior unsecured notes on November 15, 2013. A summary of these outstanding notes at March 31, is as follows:



	(In thousands, except weighted average data)		2015				2014
	Aggregate debt outstanding		$	500,000				500,000
	Weighted average remaining life in years			8.4				9.4
	Weighted average coupon rate on notes outstanding			4.86	%			4.86	%
	Fair value of debt outstanding			516,879				520,979

	The multiple series of notes totaling $500 million were issued with maturities ranging from approximately seven to 12 years. The notes may be retired before their respective scheduled maturity dates subject only to a customary make-whole provision. The terms of the notes require that the company maintain a ratio of consolidated debt to consolidated total capitalization that does not exceed 55% and maintain a ratio of consolidated EBITDA to consolidated interest charges, including capitalized interest, of not less than 3.0 to 1.0.



	August 2011 Senior Notes

	On August 15, 2011, the company issued $165 million of senior unsecured notes to a group of institutional investors. A summary of these outstanding notes at March 31, is as follows:



	(In thousands, except weighted average data)			2015				2014
	Aggregate debt outstanding		$	165,000				165,000
	Weighted average remaining life in years			5.6				6.6
	Weighted average coupon rate on notes outstanding			4.42	%			4.42	%
	Fair value of debt outstanding			167,910				168,653

	The multiple series of notes were originally issued with maturities ranging from approximately eight to 10 years. The notes may be retired before their respective scheduled maturity dates subject only to a customary make-whole provision. The terms of the notes require that the company maintain a ratio of consolidated debt to consolidated total capitalization that does not exceed 55%.

	September 2010 Senior Notes

	In fiscal 2011, the company completed the sale of $425 million of senior unsecured notes. A summary of the aggregate amount of these outstanding notes at March 31, is as follows:



	(In thousands, except weighted average data)			2015				2014
	Aggregate debt outstanding		$	425,000				425,000
	Weighted average remaining life in years			4.6				5.6
	Weighted average coupon rate on notes outstanding			4.25	%			4.25	%
	Fair value of debt outstanding			431,296				436,254

	The multiple series of these notes were originally issued with maturities ranging from five to 12 years. The notes may be retired before their respective scheduled maturity dates subject only to a customary make-whole provision. The terms of the notes require that the company maintain a ratio of consolidated debt to consolidated total capitalization that does not exceed 55%.

	Included in accumulated other comprehensive income at March 31, 2015 and 2014, is an after-tax loss of $1.8 million ($2.6 million pre-tax), and $2.4 million ($3.7 million pre-tax), respectively, relating to the purchase of interest rate hedges, which are cash flow hedges, in July 2010 in connection with the September 2010 senior notes offering. The interest rate hedges settled in August 2010 concurrent with the pricing of the senior unsecured notes. The hedges met the effectiveness criteria and their acquisition costs are being amortized to interest expense over the term of the individual notes matching the term of the hedges to interest expense.

	Notes totaling $42.5 million will mature in December 2015 but are not classified as current maturities of long-term debt because the company has the ability, if necessary, to fund this maturity with its credit facility.

	July 2003 Senior Notes

In July 2003, the company completed the sale of $300 million of senior unsecured notes. A summary of the aggregate amount of these outstanding notes at March 31, is as follows:



(In thousands, except weighted average data)			2015				2014
Aggregate debt outstanding		$	35,000				35,000
Weighted average remaining life in years			0.3				1.3
Weighted average coupon rate on notes outstanding			4.61	%			4.61	%
Fair value of debt outstanding			35,197				36,018

The multiple series of notes were originally issued with maturities ranging from seven to 12 years. These notes can be retired in whole or in part prior to maturity for a redemption price equal to the principal amount of the notes redeemed plus a customary make-whole premium. The terms of the notes require that the company maintain a ratio of consolidated debt to consolidated total capitalization that does not exceed 55%.



Notes totaling $35 million will mature in July 2015 but are not classified as current maturities of long-term debt because the company has the ability, if necessary, to fund this maturity with its credit facility.

Troms Offshore Debt

In March 2015, Troms Offshore entered into a $29.5 million, U.S. dollar denominated, 12 year unsecured borrowing agreement which matures in January 2027 and is secured by a company guarantee. The loan requires semi-annual principal payments of $1.2 million (plus accrued interest) and bears interest at a fixed rate of 2.91% plus a premium based on Tidewater Inc.’s consolidated funded indebtedness to total capitalization ratio (currently equal to 1.30% for a total all-in rate of 4.21%). As of March 31, 2015, $29.5 million is outstanding under this agreement.

In January 2014, Troms Offshore entered into a 300 million NOK, 12 year unsecured borrowing agreement which matures in January 2026 and is secured by a company guarantee. The loan requires semi-annual principal payments of 12.5 million NOK (plus accrued interest) and bears interest at a fixed rate of 2.31% plus a premium based on Tidewater Inc.’s consolidated funded indebtedness to total capitalization ratio (currently equal to 1.50% for a total all-in rate of 3.81%). As of March 31, 2015, 275 million NOK (approximately $34.2 million) is outstanding under this agreement.

In May 2012, Troms Offshore entered into a 204.4 million NOK denominated borrowing agreement which matures in May 2024. The loan requires semi-annual principal payments of 8.5 million NOK (plus accrued interest), bears interest at a fixed rate of 6.38% and is secured by certain guarantees and various types of collateral, including a vessel. In January 2014, the loan was amended to, among other things, change the interest rate to a fixed rate equal to 3.88% plus a premium based on Tidewater’s funded indebtedness to capitalization ratio (currently equal to 1.50% for a total all-in rate of 5.38%), change the borrower, change the export creditor guarantor, and to replace the vessel security with a company guarantee. As of March 31, 2015, 161.9 million NOK (approximately $20.2 million) is outstanding under this agreement.

In May 2012, Troms Offshore entered into a 35 million NOK denominated borrowing agreement with a shipyard which had one payment of 15 million NOK repaid in May 2014 and the remaining 20 million NOK maturity will be repaid in May 2015. In June 2013, Troms Offshore entered into a 25 million NOK denominated borrowing agreement a Norwegian Bank, which matures in June 2019. These borrowings bear interest based on three month NIBOR plus a credit spread of 2.0% to 3.5%. As of March 31, 2015 45 million NOK (approximately $5.6 million) is outstanding under these agreements.

Troms Offshore had 45 million NOK, or approximately $5.6 million, outstanding in floating rate debt at March 31, 2015 (whose fair value approximates the carrying value because the borrowings bear interest at variable NIBOR rates plus a margin). Troms Offshore also had 436.9 million NOK, or $54.4 million, of outstanding fixed rate debt at March 31, 2015, which has an estimated fair value of 435 million NOK, or $54.1 million as well as $29.5 million, of U.S. dollar denominated outstanding fixed rate debt at March 31, 2015, which has an estimated fair value of $29.5 million. These estimated fair values are based on Level 2 inputs.

In June 2013, Troms Offshore repaid a 188.9 million NOK loan (approximately $32.5 million), plus accrued interest that was secured with various guarantees and collateral, including a vessel.

During the second quarter of fiscal 2014, the company repaid prior to maturity 500 million Norwegian Kroner (NOK) denominated (approximately $82.1 million) public bonds (plus accrued interest) that had been issued by Troms Offshore in April 2013. The repayment of these bonds, at an average price of approximately 105.0% of par value, resulted in the recognition of a loss on early extinguishment of debt of approximately 26 million NOK (approximately $4.1 million).



Summary of Long-Term Debt Outstanding

The following table summarizes debt outstanding at March 31:



(In thousands)			2015				2014
4.61% July 2003 senior notes due fiscal 2016		$	35,000				35,000
3.28% September 2010 senior notes due fiscal 2016			42,500				42,500
3.90% September 2010 senior notes due fiscal 2018			44,500				44,500
3.95% September 2010 senior notes due fiscal 2018			25,000				25,000
4.12% September 2010 senior notes due fiscal 2019			25,000				25,000
4.17% September 2010 senior notes due fiscal 2019			25,000				25,000
4.33% September 2010 senior notes due fiscal 2020			50,000				50,000
4.51% September 2010 senior notes due fiscal 2021			100,000				100,000
4.56% September 2010 senior notes due fiscal 2021			65,000				65,000
4.61% September 2010 senior notes due fiscal 2023			48,000				48,000
4.06% August 2011 senior notes due fiscal 2019			50,000				50,000
4.54% August 2011 senior notes due fiscal 2022			65,000				65,000
4.64% August 2011 senior notes due fiscal 2022			50,000				50,000
4.26% September 2013 senior notes due fiscal 2021			123,000				123,000
5.01% September 2013 senior notes due fiscal 2024			250,000				250,000
5.16% September 2013 senior notes due fiscal 2026			127,000				127,000
NOK denominated notes due fiscal 2025			20,152				29,837
NOK denominated notes due fiscal 2026			34,234				50,028
NOK denominated borrowing agreement due fiscal 2016			2,490				5,837
NOK denominated borrowing agreement due fiscal 2019			3,112				4,168
USD denominated notes due fiscal 2027			29,488				—
Bank term loan due fiscal 2019 (A)			300,000				300,000
Revolving line of credit due fiscal 2019 (A)			20,000				—
		$	1,534,476				1,514,870
Less: Current maturities of long-term debt			10,181				9,512
Total		$	1,524,295				1,505,358



(A)	In May 2015, the company amended its existing credit facility, extending the due dates of the bank term loan and revolving line of credit until fiscal 2020. Refer to Note (19) for additional information regarding the amended and extended credit facility.

Debt Costs

The company capitalizes a portion of its interest costs incurred on borrowed funds used to construct vessels. Interest and debt costs incurred, net of interest capitalized, for the years ended March 31, are as follows:



(In thousands)		2015				2014				2013
Interest and debt costs incurred, net of interest capitalized		$	50,029				43,814				29,745
Interest costs capitalized			13,673				11,497				10,602
Total interest and debt costs		$	63,702				55,311				40,347

Employee_Retirement_Plans

Employee Retirement Plans	12 Months Ended
Employee Retirement Plans	Mar. 31, 2015
Employee Retirement Plans	-6		EMPLOYEE RETIREMENT PLANS

	U.S. Defined Benefit Pension Plan

	The company has a defined benefit pension plan (pension plan) that covers certain U.S. citizen employees and other employees who are permanent residents of the United States. Benefits are based on years of service and employee compensation. In December 2009, the Board of Directors amended the pension plan to discontinue the accrual of benefits once the plan was frozen on December 31, 2010. On that date, previously accrued pension benefits under the pension plan were frozen for the approximately 60 active employees who participated in the plan. As of March 31, 2015, approximately 45 employees are covered by this plan. This change did not affect benefits earned by participants prior to January 1, 2011. Active employees who previously accrued benefits under the pension plan continue to accrue benefits as participants in the company’s defined contribution retirement plan effective January 1, 2011. The transfer of employee benefits from a defined benefit pension plan to a defined contribution plan have provided the company with more predictable retirement plan costs and cash flows. The company’s future benefit obligations and requirements for cash contributions for the frozen pension plan have also been reduced. Losses associated with the curtailment of the pension plan were immaterial. No amounts were contributed to the defined benefit pension plan during fiscal 2015 and 2014. Management is working with its actuary to determine if a contribution will be necessary during fiscal 2016.



	Supplemental Executive Retirement Plan

	The company also offers a non-contributory, defined benefit supplemental executive retirement plan (supplemental plan) that provides pension benefits to certain employees in excess of those allowed under the company’s tax-qualified pension plan. A Rabbi Trust has been established for the benefit of participants in the supplemental plan. The Rabbi Trust assets, which are invested in a variety of marketable securities (but not Tidewater stock) are recorded at fair value with unrealized gains or losses included in other comprehensive income. Effective March 4, 2010, the supplemental plan was closed to new participation. The supplemental plan is a non-qualified plan and, as such, the company is not required to make contributions to the supplemental plan. The company did not contribute to the supplemental plan during fiscal 2015 and 2014. Management has not made any decision on funding the plan during fiscal 2016.

	As a result of the May 31, 2012 retirement of Dean E. Taylor, former President and Chief Executive Officer of Tidewater Inc., Mr. Taylor received in December 2012 a $13 million lump sum distribution in full settlement and discharge of his supplemental executive retirement plan benefit. A settlement loss of $5.2 million related to this distribution was recorded in general and administrative expenses during the quarter ended December 31, 2012. The settlement loss is the result of the recognition of previously unrecognized actuarial losses that were being amortized over time from accumulated other comprehensive income to pension expense. As a result of the December 2012 lump sum distribution, a portion of the previously unrecognized actuarial losses was required to be recognized in earnings in the current quarter in accordance with ASC 715.

	Investments held in a Rabbi Trust in the supplemental plan are included in other assets at fair value. The following table summarizes the carrying value of the trust assets, including unrealized gains or losses at March 31:



	(In thousands)		2015				2014
	Investments held in Rabbi Trust		$	9,915				10,285
	Unrealized (loss) gains in carrying value of trust assets			235				92
	Unrealized (loss) gains in carrying value of trust assets are net of income tax expense of			126				49
	Obligations under the supplemental plan			25,510				21,918

	The unrealized gains or losses in the carrying value of the trust assets, net of income tax expense, are included in accumulated other comprehensive income (other stockholders’ equity). To the extent that trust assets are liquidated to fund benefit payments, gains or losses, if any, will be recognized at that time. The company’s obligations under the supplemental plan are included in ‘accrued expenses’ and ‘other liabilities and deferred credits’ on the consolidated balance sheet.

	Postretirement Benefit Plan

	Qualified retired employees currently are covered by a program which provides limited health care and life insurance benefits. Costs of the program are based on actuarially determined amounts and are accrued over the period from the date of hire to the full eligibility date of employees who are expected to qualify for these benefits. This plan is funded through payments as benefits are required.

	Investment Strategies

	Pension Plan

	The obligations of our pension plan are supported by assets held in a trust for the payment of future benefits. The company is obligated to adequately fund the trust. For the pension plan assets, the company has the following primary investment objectives: (1) closely match the cash flows from the plan’s investments from interest payments and maturities with the payment obligations from the plan’s liabilities; (2) closely match the duration of plan assets with the duration of plan liabilities and (3) enhance the plan’s investment returns without taking on undue risk by industries, maturities or geographies of the underlying investment holdings.



	If the plan assets are less than the plan liabilities, the pension plan assets will be invested exclusively in fixed income debt securities. Any investments in corporate bonds shall be at least investment grade, while mortgage and asset-backed securities must be rated “A” or better. If an investment is placed on credit watch, or is downgraded to a level below the investment grade, the holding will be liquidated, even at a loss, in a reasonable time period. The plan will only hold investments in equity securities if the plan assets exceed the estimated plan liabilities.

	The cash flow requirements of the pension plan will be analyzed at least annually. Portfolio repositioning will be required when material changes to the plan liabilities are identified and when opportunities arise to better match cash flows with the known liabilities. Additionally, trades will occur when opportunities arise to improve the yield-to-maturity or credit quality of the portfolio.

	The company’s policy for the pension plan is to contribute no less than the minimum required contribution by law and no more than the maximum deductible amount. The plan does not invest in Tidewater stock.

	Supplemental Plan

	The investment policy of the supplemental plan is to assess the historical returns and risk associated with alternative investment strategies to achieve an expected rate of return on plan assets. The objectives of the plan are designed to maximize total returns within prudent parameters of risk for a retirement plan of this type. The below table summarizes the supplemental plan’s minimum and maximum rate of return objectives for plan assets:



			Minimum		Maximum
			Expected		Expected
			Rate of Return		Rate of Return
			on Plan Assets		on Plan Assets
	Equity securities		5%		7%
	Debt securities		1%		3%
	Cash and cash equivalents		0%		1%

	Whereas fluctuating rates of return are characteristic of the securities markets, the investment objective of the supplemental plan is to achieve investment returns sufficient to meet the actuarial assumptions. This is defined as an investment return greater than the current actuarial discount rate assumption of 4.00%, which is subject to annual upward or downward revisions.

	The below table summarizes the supplemental plan’s minimum and maximum market value objectives for plan assets, which are based upon a five to ten year investment horizon:



		Minimum		Maximum
		Market Value		Market Value
		Objective for		Objective for
		Plan Assets		Plan Assets
Equity securities		55%		75%
Debt securities		25%		45%
Percentage of debt securities allowed in below investment grade bonds		0%		20%
Cash and cash equivalents		0%		10%

Equity holdings shall be restricted to issues of corporations that are actively traded on the major U.S. exchanges and NASDAQ. Debt security investments may include all securities issued by the U.S. Treasury or other federal agencies and investment grade corporate bonds. When a particular asset class exceeds its minimum or maximum allocation ranges, rebalancing will be addressed upon review of the quarterly performance reports and as cash contributions and withdrawals are made.



Pension and Supplemental Plan Asset Allocations

The following table provides the target and actual asset allocations for the pension plan and the supplemental plan:



		Target				Actual as of			Actual as of
		Target				2015			2014
Pension plan:
Equity securities			—				—			—
Debt securities			100	%			95	%		96	%
Cash and other			—				5	%		4	%
Total			100	%			100	%		100	%

Supplemental plan:
Equity securities			65	%			58	%		60	%
Debt securities			35	%			39	%		37	%
Cash and other			—				3	%		3	%
Total			100	%			100	%		100	%


Significant Concentration Risks

The pension plan and the supplemental plan assets are periodically evaluated for concentration risks. As of March 31, 2015, the company did not have any individual asset investments that comprised 10% or more of each plan’s overall assets.

The pension plan assets are primarily invested in debt securities with no more than the greater of 5% of the fixed income portfolio or $2.5 million being invested in the securities of a single issuer, except investments in U.S. Treasury and other federal agency obligations. In the event that plan assets exceed the estimated plan liabilities for the pension plan, up to two times the difference between the plan assets and plan liabilities may be invested in equity securities, and so long as equities do not exceed 15% of the market value of the assets. The investment policy sets forth that the maximum single investment of the equity portfolio is 5% of the portfolio market value. Further, investments in foreign securities are restricted to American Depository Receipts (ADR) and stocks listed on the U.S. stock exchanges and may not exceed 10% of the equity portfolio.

The current diversification policy for the supplemental plan sets forth that equity securities in any single industry sector shall not exceed 25% of the equity portfolio market value and shall not exceed 10% market value of the equity portfolio for equity holdings in any single corporation. Additionally, debt securities should be diversified between issuers within each sector with no one issuer comprising more than 10% of the aggregate fixed income portfolio, excluding issues of the U.S. Treasury or other federal agencies.



Fair Value of Pension Plan and Supplemental Plan Assets

The fair value hierarchy for the pension plan and supplemental plan assets measured at fair value as of March 31, 2015, are as follows:



(In thousands)		Fair Value				Quoted prices in			Significant			Significant
						active			observable			unobservable
						markets			inputs			inputs
						(Level 1)			(Level 2)			(Level 3)
Pension plan measured at fair value:
Debt securities:
Government securities		$	3,116				3,116			—			—
Collateralized mortgage securities			400				—			400			—
Corporate debt securities			51,758				—			51,758			—
Foreign debt securities			1,529				—			1,529			—
Cash and cash equivalents			1,816				—			1,816			—
Total		$	58,619				3,116			55,503			—
Accrued income			866				866			—			—
Total fair value of plan assets		$	59,485				3,982			55,503			—

Supplemental plan measured at fair value:
Equity securities:
Common stock		$	3,859				3,859			—			—
Preferred stock			—				—			—			—
Foreign stock			201				201			—			—
American depository receipts			1,685				1,685			—			—
Preferred American depository receipts			15				15			—			—
Real estate investment trusts			59				59			—			—
Debt securities:
Government debt securities			1,926				1,377			549			—
Open ended mutual funds			1,916				1,916			—			—
Cash and cash equivalents			377				72			305			—
Total		$	10,038				9,184			854			—
Other pending transactions			(123	)			(123	)		—			—
Total fair value of plan assets		$	9,915				9,061			854			—




The following table provides the fair value hierarchy for the pension plan and supplemental plan assets measured at fair value as of March 31, 2014:



(In thousands)		Fair Value				Quoted prices in			Significant			Significant
						active			observable			unobservable
						markets			inputs			inputs
						(Level 1)			(Level 2)			(Level 3)
Pension plan measured at fair value:
Debt securities:
Government securities		$	2,935				2,935			—			—
Corporate debt securities			50,113				—			50,113			—
Foreign debt securities			1,443				—			1,443			—
Cash and cash equivalents			1,511				—			1,511			—
Total		$	56,002				2,935			53,067			—
Accrued income			894				894			—			—
Total fair value of plan assets		$	56,896				3,829			53,067			—

Supplemental plan measured at fair value:
Equity securities:
Common stock		$	4,141				4,141			—			—
Preferred stock			—				—			—			—
Foreign stock			231				231			—			—
American depository receipts			1,809				1,809			—			—
Preferred American depository receipts			15				15			—			—
Real estate investment trusts			38				38			—			—
Debt securities:
Government debt securities			1,975				1,363			612			—
Open ended mutual funds			1,797				1,797			—			—
Cash and cash equivalents			369				57			312			—
Total		$	10,375				9,451			924			—
Other pending transactions			(90	)			(90	)		—			—
Total fair value of plan assets		$	10,285				9,361			924			—




Plan Assets and Obligations

Changes in plan assets and obligations during the years ended March 31, 2015 and 2014 and the funded status of the U.S. defined benefit pension plan and the supplemental plan (referred to collectively as “Pension Benefits”) and the postretirement health care and life insurance plan (referred to as “Other Benefits”) at March 31, are as follows:



		Pension Benefits							Other Benefits
(In thousands)		2015				2014			2015			2014
Change in benefit obligation:
Benefit obligation at beginning of year		$	84,067				88,238			24,114			29,006
Service cost			825				790			273			405
Interest cost			3,873				3,581			904			1,048
Participant contributions			—				—			430			436
ERRP reimbursement			—				—			—			(26	)
Plan settlement			—				—			—			—
Benefits paid			(4,405	)			(4,250	)		(863	)		(962	)
Actuarial (gain) loss			11,948				(4,292	)		(932	)		(5,793	)
Benefit obligation at end of year			96,308				84,067			23,926			24,114

Change in plan assets:
Fair value of plan assets at beginning of year		$	56,896				59,431			—			—
Actual return			6,069				776			—			—
Employer contributions			925				939			433			552
Participant contributions			—				—			430			436
ERRP reimbursement			—				—			—			(26	)
Plan settlement			—				—			—			—
Benefits paid			(4,405	)			(4,250	)		(863	)		(962	)
Fair value of plan assets at end of year			59,485				56,896			—			—


Reconciliation of funded status:
Fair value of plan assets		$	59,485				56,896			—			—
Benefit obligation			96,308				84,067			23,926			24,114
Unfunded status		$	(36,823	)			(27,171	)		(23,926	)		(24,114	)


Net amount recognized in the balance sheet consists of:
Current liabilities		$	(1,306	)			(1,162	)		(908	)		(1,129	)
Noncurrent liabilities			(35,517	)			(26,009	)		(23,018	)		(22,985	)
Net amount recognized		$	(36,823	)			(27,171	)		(23,926	)		(24,114	)


The following table provides the projected benefit obligation and accumulated benefit obligation for the pension plans:



(In thousands)		2015				2014
Projected benefit obligation		$	96,308				84,067
Accumulated benefit obligation			92,808				81,223



The following table provides information for pension plans with an accumulated benefit obligation in excess of plan assets (includes both the pension plan and supplemental plan):



(In thousands)		2015				2014
Projected benefit obligation		$	96,308				84,067
Accumulated benefit obligation			92,808				81,223
Fair value of plan assets			59,485				56,896

Net periodic benefit cost for the pension plan and the supplemental plan for the fiscal years ended March 31 include the following components:



(In thousands)		2015				2014			2013
Service cost		$	825				790			983
Interest cost			3,873				3,581			4,098
Expected return on plan assets			(2,741	)			(2,871	)		(2,748	)
Amortization of prior service cost			50				50			50
Recognized actuarial loss			988				1,103			1,648
Settlement loss			—				—			5,161
Net periodic pension cost		$	2,995				2,653			9,192


Net periodic benefit cost for the postretirement health care and life insurance plan for the fiscal years ended March 31 include the following components:



(In thousands)		2015				2014			2013
Service cost		$	273				405			475
Interest cost			904				1,048			1,235
Amortization of prior service cost			(2,032	)			(2,032	)		(2,032	)
Recognized actuarial loss			(1,299	)			(396	)		—
Net periodic postretirement benefit		$	(2,154	)			(975	)		(322	)


Other changes in plan assets and benefit obligations recognized in other comprehensive income for the fiscal years ended March 31 include the following components:



		Pension Benefits							Other Benefits
(In thousands)		2015				2014			2015			2014
Change in benefit obligation
Net loss (gain)			$ 8,621				(2,196	)		(932	)		(5,793	)
Settlement loss			—				—			—			—
Amortization of prior service cost			(50	)			(50	)		2,032			2,032
Amortization of net (loss) gain			(988	)			(1,103	)		1,299			395
Other			—				—			—			197
Total recognized in other comprehensive income (loss)			$ 7,583				(3,349	)		2,399			(3,169	)
Net of tax			7,583				(2,177	)		1,559			(2,060	)


Amounts recognized as a component of accumulated other comprehensive (income) loss as of March 31, 2015 are as follows:



(In thousands)		Pension Benefits				Other Benefits
Unrecognized actuarial (gain) loss			$ 21,781				(6,620	)
Unrecognized prior service cost (benefit)			36				(4,588	)
Pre-tax amount included in accumulated other comprehensive loss (income)			$ 21,817				(11,208	)


The company expects to recognize the following amounts as a component of net periodic benefit costs during the next fiscal year:



(In thousands)		Pension Benefits				Other Benefits
Unrecognized actuarial loss			$ (2,213)				582
Unrecognized prior service cost (benefit)			-36				2,041



Assumptions used to determine net benefit obligations for the fiscal years ended March 31, are as follows:



		Pension Benefits							Other Benefits
		2015				2014			2015			2014
Discount rate			4.00%				4.75%			4.00%			4.75%
Rates of annual increase in compensation levels			3.00%				3.00%			N/A			N/A

Assumptions used to determine net periodic benefit costs for the fiscal years ended March 31, are as follows:



		Pension Benefits										Other Benefits
		2015				2014			2013			2015			2014		2013
Discount rate			4.75%				4.25%			4.75%			4.75%			4.25%		4.75%
Expected long-term rate of return on assets			5.00%				5.00%			5.00%			N/A			N/A		N/A
Rates of annual increase in compensation levels			3.00%				3.00%			3.00%			N/A			N/A		N/A

To develop the expected long-term rate of return on assets assumption, the company considered the current level of expected returns on various asset classes. The expected return for each asset class was then weighted based on the target asset allocation to develop the expected return on plan assets assumption for the portfolio.

Based upon the assumptions used to measure the company’s qualified pension and postretirement benefit obligations at March 31, 2015, including pension and postretirement benefits attributable to estimated future employee service, the company expects that benefits to be paid over the next ten years will be as follows:



		(In thousands)
Year ending March 31,		Pension				Other
Year ending March 31,		Benefits				Benefits
2016			$ 5,578				908
2017			5,818				982
2018			6,077				1,046
2019			6,343				1,128
2020			7,419				1,187
2021 – 2025			33,918				6,501
Total 10-year estimated future benefit payments			$ 65,153				11,752


Health Care Cost Trends

The following table discloses the assumed health care cost trends used in measuring the accumulated postretirement benefit obligation and net periodic postretirement benefit cost at March 31, 2015 for pre-65 medical and prescription drug coverage and for post-65 medical coverage, including expected future trend rates.



		Pre-65				Post-65
Year ending March 31, 2015
Accumulated postretirement benefit obligation			7.9	%			6.9	%
Net periodic postretirement benefit obligation			8.2	%			6.9	%
Ultimate health care cost trend			4.5	%			4.5	%
Ultimate year health care cost trend rate is achieved			2029				2029
Year ending March 31, 2016
Net periodic postretirement benefit obligation			7.9	%			6.9	%

A one-percentage rate increase (decrease) in the assumed health care cost trend rates has the following effects on the accumulated postretirement benefit obligation as of March 31:



(In thousands)		1%				1%
(In thousands)		Increase				Decrease
Accumulated postretirement benefit obligation		$	3,702				2,978
Aggregate service and interest cost			170				138



Defined Contribution Plans

Prior to February 2013, the company maintained the below two defined contribution plans. The plans were merged in February 2013 to provide administrative efficiencies, potential savings on service provider fees and to simplify the participant experience. Following the merger, the provisions of the two plans remained substantially similar with the exception of cost neutral changes that were approved to simplify the administration of the combined plan.

Retirement Contributions

All eligible U.S. fleet personnel, along with all new eligible employees of the company hired after December 31, 1995 are eligible to receive retirement contributions. Effective January 1, 2011, the active employees who participated in the now frozen defined benefit pension plan also became eligible for retirement contributions. This benefit is noncontributory by the employee, but the company contributes, in cash, 3% of an eligible employee’s compensation to a trust on behalf of the employees. The active employees who participated in the now frozen defined benefit pension plan may receive an additional 1% to 8% depending on age and years of service. Company contributions vest over five years.

401(k) Savings Contribution

Upon meeting various citizenship, age and service requirements, employees are eligible to participate in a defined contribution savings plan and can contribute from 2% to 75% of their base salary to an employee benefit trust. The company matches with company common stock 50% of the first 8% of eligible compensation deferred by the employee. Company contributions vest over five years.

The plan held the following number of shares of Tidewater common stock as of March 31:



		2015				2014
Number of shares of Tidewater common stock held by 401(k) plan			299,256				273,662

The amounts charged to expense related to the above defined contribution plans, for the fiscal years ended March 31, are as follows:



(In thousands)		2015				2014			2013
Defined contribution plans expense, net of forfeitures			$ 4,216				3,854			3,356
Defined contribution plans forfeitures			52				82			115

Other Plans

A non-qualified supplemental savings plan is provided to executive officers who have the opportunity to defer up to 50% of their eligible compensation that cannot be deferred under the existing 401(k) plan due to IRS limitations. A company match may be provided on these contributions equal to 50% of the first 8% of eligible compensation deferred by the employee to the extent the employee is not able to receive the full amount of company match to the 401(k) plan due to IRS limitations. The plan also allows participants to defer up to 100% of their bonuses. In addition, an amount equal to any refunds that must be made due to the failure of the 401(k) nondiscrimination test may be deferred into this plan.

Effective March 4, 2010, the non-qualified supplemental savings plan was modified to allow the company to contribute restoration benefits to eligible employees. Employees who do not accrue a benefit in the supplemental executive retirement plan and who are eligible for a contribution in the defined contribution retirement plan automatically become eligible for the restoration benefit when the employee’s eligible retirement compensation exceeds the section 401(a)(17) limit. The restoration benefit is noncontributory by the employee, but the company contributes, in cash, 3% of an eligible employee’s compensation above the 401(a)(17) limit to a trust on behalf of the employees. The active employees who participated in the now frozen defined benefit pension plan may receive an additional 1% to 8% depending on age and years of service.



The company also provides a multinational savings plan to eligible non-U.S. citizen employees working outside their respective country of origin and who have been employed for one year of continuous service with the company. Participants of the plan may contribute 1% to 15% of their base salary. The company matches, in cash, 50% of the first 6% of eligible compensation deferred by the employee. Company contributions vest over six years.

The amounts charged to expense related to the multinational pension savings plan contributions, for the fiscal years ended March 31, are as follows:



(In thousands)		2015				2014			2013
Multinational pension savings plan expense		$	494				465			420

The company also provides certain benefits programs which are maintained in several other countries that provide retirement income for covered employees.

Other_Assets_Accrued_Expenses_

Other Assets, Accrued Expenses, Other Current Liabilities, and Other Liabilities and Deferred Credits	12 Months Ended
	Mar. 31, 2015
Other Assets, Accrued Expenses, Other Current Liabilities, and Other Liabilities and Deferred Credits	-7	OTHER ASSETS, ACCRUED EXPENSES, OTHER CURRENT LIABILITIES, AND OTHER LIABILITIES AND DEFERRED CREDITS

	A summary of other assets at March 31, is as follows:



	(In thousands)	2015		2014
	Recoverable insurance losses		$ 10,468		5,219
	Deferred income tax assets		19,004		34,376
	Deferred finance charges – revolver		7,396		8,728
	Savings plans and supplemental plan		23,208		23,212
	Noncurrent tax receivable		—		9,106
	Other		15,120		15,744
			$ 75,196		96,385


	A summary of accrued expenses at March 31, is as follows:



	(In thousands)	2015		2014
	Payroll and related payables		$ 32,041		27,248
	Commissions payable		8,282		8,263
	Accrued vessel expenses		79,549		96,468
	Accrued interest expense		14,514		14,816
	Other accrued expenses		11,869		10,507
			$ 146,255		157,302


	A summary of other current liabilities at March 31, is as follows:



	(In thousands)	2015		2014
	Taxes payable	$	56,620		56,080
	Deferred gain on vessel sales - current		25,057		13,996
	Other		784		491
		$	82,461		70,567


	A summary of other liabilities and deferred credits at March 31, is as follows:



	(In thousands)	2015		2014
	Postretirement benefits liability	$	23,018		23,185
	Pension liabilities		41,279		35,234
	Deferred gain on vessel sales		136,238		85,316
	Other		34,573		35,469
		$	235,108		179,204

StockBased_Compensation_and_In

Stock-Based Compensation and Incentive Plans	12 Months Ended
Stock-Based Compensation and Incentive Plans	Mar. 31, 2015
Stock-Based Compensation and Incentive Plans	-8		STOCK-BASED COMPENSATION AND INCENTIVE PLANS
	The company’s employee stock option, restricted stock awards, restricted stock units (that settle in Tidewater common stock), phantom stock, and cash-based performance unit plans, are long-term retention plans that are intended to attract, retain and provide incentives for talented employees, including officers and non-employee directors, and to align stockholder and employee interests. The company believes its employee restricted stock, stock unit and stock option plans are critical to its operations and productivity. The employee stock option plans allow the company to grant, on a discretionary basis, both incentive and non-qualified stock options as well as restricted stock. The restricted stock and stock unit awards include performance shares.
	Under the company’s stock option and restricted stock plans, the Compensation Committee of the Board of Directors has the authority to grant stock options, restricted shares and restricted stock units of the company’s stock to officers and other key employees. Under the terms of the plans, stock options are granted with an exercise price equal to the stock’s closing fair market value on the date of grant.
	The number of common stock shares reserved for issuance under the plans and the number of shares available for future grants at March 31, are as follows:


			March 31,
			2015
	Shares of common stock reserved for issuance under the plans			2,580,880
	Shares of common stock available for future grants			871,674
	Stock Option Plans
	The company has granted stock options to its directors and employees, including officers, under several different stock incentive plans. Generally, options granted vest annually over a three-year vesting period measured from the date of grant. Options not previously exercised expire at the earlier of either three months after termination of the grantee’s employment or ten years after the date of grant. Upon retirement, unvested stock options are forfeited. The retiree has two years post retirement to exercise vested options. All of the stock options are classified as equity awards.
	The company uses the Black-Scholes option-pricing model to determine the fair value of options granted and to calculate the share-based compensation expense. Stock options were granted in fiscal 2015 but not during fiscal 2014 and 2013. The fair value and assumptions used for the stock options issued during the year ended March 31, 2015, are as follows:


			2015
	Weighted average fair value of stock options granted			$5.54
	Risk-free interest rate			1.82%
	Expected dividend yield			2.40%
	Expected stock price volatility			30%
	Expected stock option life			6.5 years

	The following table sets forth a summary of stock option activity of the company for fiscal years 2015, 2014 and 2013:


			Weighted-average			Number of
			Exercise Price			Shares
	Outstanding at March 31, 2012			$ 44.93			1,725,424
	Granted			—			—
	Exercised			29.09			(141,542	)
	Expired or cancelled/forfeited			52.47			(27,607	)
	Outstanding at March 31, 2013			46.24			1,556,275
	Granted			—			—
	Exercised			36.86			(186,219	)
	Expired or cancelled/forfeited			—			—
	Outstanding at March 31, 2014			47.51			1,370,056
	Granted			22.80			428,326
	Exercised			35.21			(29,118	)
	Expired or cancelled/forfeited			42.97			(60,058	)
	Outstanding at March 31, 2015			$ 41.69			1,709,206

	Information regarding the 1,709,206 options outstanding at March 31, 2015 can be grouped into three general exercise-price ranges as follows:


			Exercise Price Range
	At March 31, 2015		$22.80 - $33.83			$45.75 - $48.96				$55.76 - $65.69
	Options outstanding			728,287			394,515				586,404
	Weighted average exercise price of options outstanding			$27.34			$45.86				$56.70
	Weighted average remaining contractual life of options outstanding			7.5 years			5.0 years				2.0 years
	Options exercisable			307,488			394,515				586,404
	Weighted average exercise price of options exercisable			$33.56			$45.86				$56.70
	Weighted average remaining contractual life of options exercisable			4.1 years			5.0 years				2.0 years

	Additional information regarding stock options for the years ended March 31, are as follows:


	(In thousands, except number of stock options and weighted average price)		2015			2014				2013
	Intrinsic value of options exercised		$	475			4,059				2,544
	Number of stock options vested			7,527			8,926				144,537
	Fair value of stock options vested		$	40			115				2,154
	Number of options exercisable			1,288,407			1,370,056				1,547,349
	Weighted average exercise price of options exercisable		$	47.86			47.51				46.27

	There was no intrinsic value of any options outstanding or exercisable at March 31, 2015.

Stock option compensation expense along with the reduction effect on basic and diluted earnings per share, and stock option compensation expense for the years ended March 31, are as follows:

(In thousands, except per share data)		2015			2014				2013
Stock option compensation expense		$	71			12				2,049
Basic earnings per share reduced by			0			0				0.03
Diluted earnings per share reduced by			0			0				0.03
As of March 31, 2015, total unrecognized stock-option compensation costs amounted to $2.3 million or $1.3 million net of tax. No stock option compensation costs were capitalized as part of the cost of an asset. Compensation costs for stock options that have not yet vested will be recognized as the underlying stock options vest over the appropriate future period. The level of unrecognized stock-option compensation will be affected by any future stock option grants and by the termination of any employee who has received stock options that are unvested as of the employee’s termination date.

Restricted Stock Awards
The company has granted restricted stock awards to key employees, including officers, under several different employee stock plans, which provide for the granting of restricted stock and/or performance awards to officers and key employees. The company awards both time-based and performance-based shares of restricted stock awards. The restrictions on the time-based restricted stock awards lapse generally over a four year period and require no goals to be achieved other than the passage of time and continued employment. The restrictions on the performance-based restricted stock award lapse if the company meets specific targets. During the restricted period, the restricted shares may not be transferred or encumbered, but the recipient has the right to vote the restricted shares and receive dividends on the time-based restricted shares. Dividends are accrued on performance-based restricted shares and ultimately paid only if the performance criteria are achieved. All of the restricted stock awards are classified as equity awards in stockholders’ equity. The value of restricted stock awards is generally amortized on a straight-line basis to earnings over the respective vesting periods and is net of forfeitures.
The following table sets forth a summary of restricted stock award activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average			Time Based				Performance
		Grant-Date			Shares				Based Shares
		Fair Value
Non-vested balance at March 31, 2012			51.43			266,418				223,641
Granted			—			—				—
Vested			49.53			(110,802	)			—
Cancelled/forfeited			56.84			(7,067	)			(59,503	)
Non-vested balance at March 31, 2013			50.95			148,549				164,138
Granted			55.04			28,963				—
Vested			56.71			(93,739	)			(1,749	)
Cancelled/forfeited			35.76			(4,949	)			(56,123	)
Non-vested balance at March 31, 2014			$ 54.75			78,824				106,266
Granted			—			—				—
Vested			57.46			(48,574	)			—
Cancelled/forfeited			47.09			(5,959	)			(37,861	)
Non-vested balance at March 31, 2015			$ 56.94			24,291				68,405

Restrictions on approximately 24,291 time-based restricted stock awards outstanding at March 31, 2015 will lapse during fiscal 2016, and restrictions on 68,405 performance-based restricted stock awards outstanding at March 31, 2015 will lapse during fiscal 2016 if performance-based targets are achieved.
Restricted stock award compensation expense and grant date fair value for the years ended March 31, is as follows:


(In thousands)		2015			2014				2013
Grant date fair value of restricted stock vested		$	2,791			4,671				5,488
Restricted stock compensation expense			2,855			4,633				5,987
As of March 31, 2015, total unrecognized restricted stock compensation costs amounted to $0.5 million, or $0.5 million net of tax. No restricted stock award compensation costs were capitalized as part of the costs of an asset. The amount of unrecognized restricted stock compensation will be affected by any future restricted stock grants and by the separation of an employee from the company who has received restricted stock grants that are unvested as of their separation date. There were no modifications to the restricted stock awards during fiscal 2015, 2014 and 2013.
Restricted Stock Units
The company has granted restricted stock units (RSUs) to key employees, including officers, under the company’s employee stock plan, which provide for the granting of restricted stock units to officers and key employees. The company awards time-based units, where each unit represents the right to receive, at the end of a vesting period, one unrestricted share of Tidewater common stock with no exercise price. The company also awards performance-based RSUs, where each unit represents the right to receive, at the end of a vesting period, up to two shares of Tidewater common stock with no exercise price. Vesting of the various performance-based restricted stock units is based on metrics such as a three year Total Shareholder Return (TSR) as measured against a three year TSR of a defined peer group and Return on Total Capital (ROTC) for the company over a three year performance period. The company uses assumptions underlying the Black-Scholes methodology to produce a Monte Carlo simulation model to value the TSR performance-based restricted stock units. The fair value of the ROTC performance-based RSUs and time-based RSUs is based on the market price of our common stock on the date of grant. The restrictions on the time-based RSUs lapse over a three year period from the date of the award and require no goals to be achieved other than the passage of time and continued employment. The restrictions on the performance-based restricted stock units lapse if the company meets specific targets as defined. During the restricted period, the RSUs may not be transferred or encumbered, but the recipient has the right to receive dividend equivalents on the restricted stock units, but have no voting rights until the units vest. Dividend equivalents are accrued on performance-based restricted shares and ultimately paid only if the performance criteria are achieved. Upon retirement, the Compensation Committee of the Board of Directors will take into consideration the accelerated vesting of the restricted stock units after certain age and service criteria are met. Restricted stock unit compensation costs are recognized on a straight-line basis over the vesting period, and are net of forfeitures.
The following table sets forth a summary of restricted stock unit activity of the company for fiscal 2015, 2014, and 2013:


		Weighted-average			Time				Weight-average			Performance
		Grant-Date			Based				Grant Date			Based Units
		Fair Value			Units				Fair Value
Non-vested balance at March 31, 2012			$ 54.18			248,288				72.23			84,394
Granted			50.16			259,158				67.11			84,323
Vested			54.17			(79,507)				—			—
Cancelled/forfeited			54.18			(10,274)				72.23			(3,476)
Non-vested balance at March 31, 2013			$ 51.69			417,665				69.62			165,241
Granted			49.37			265,937				56.44			91,132
Vested			52.22			(175,673)				—			—
Cancelled/forfeited			52.43			(12,720)				—			—
Non-vested balance at March 31, 2014			$ 50.24			495,209				53.58			256,373
Granted			54.48			551				—			—
Vested			50.92			(237,229)				—			—
Cancelled/forfeited			49.62			(7,381)				—			—
Non-vested balance at March 31, 2015			$ 49.50			251,150				53.58			256,373

Restrictions on approximately 156,772 time-based units and 92,194 performance-based units outstanding at March 31, 2015 will vest during fiscal 2016.
Restricted stock unit compensation expense and grant date fair value for the year ended March 31, is as follows:


(In thousands)		2015			2014				2013
Grant date fair value of restricted stock units vested		$	12,080			9,176				4,307
Restricted stock unit compensation expense			17,214			12,664				7,836
As of March 31, 2015, total unrecognized restricted stock unit compensation costs amounted to $16.6 million, or $11.4 million net of tax. No restricted stock unit compensation costs were capitalized as part of the costs of an asset. The amount of unrecognized restricted stock unit compensation costs will be affected by any future restricted stock unit grants and by the separation of an employee from the company who has received restricted stock units that are unvested as of their separation date. There were no modifications to the restricted stock units during fiscal 2015, 2014 and 2013.

Phantom Stock Plan
The company provides a Phantom Stock Plan to provide additional incentive compensation to key employees including officers of the company. The plan awards phantom stock units to participants who have the right to receive the value of a share of common stock in cash from the company. Participants have no voting or other rights as a shareholder with respect to any common stock as a result of participation in the phantom stock plan. The phantom shares generally have a three or four-year vesting period from the grant date of the award provided the employee remains employed by the company during the vesting period. Participants receive dividend equivalents at the same rate as dividends on the company’s common stock.
The following table sets forth a summary of phantom stock activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average			Time				Performance
		Grant-Date			Based				Based
		Fair Value			Shares				Shares
Non-vested balance at March 31, 2012			49.23			103,311				28,059
Granted			50.76			27,100				—
Vested			43.60			(54,823	)			—
Cancelled/forfeited			54.26			(6,993	)			(28,059	)
Non-vested balance at March 31, 2013			51.74			68,595				—
Granted			48.81			31,736				1,291
Vested			51.45			(35,095	)			—
Cancelled/forfeited			50.93			(4,354	)			—
Non-vested balance at March 31, 2014		$	50.94			60,882				1,291
Granted			22.80			546,058				—
Vested			48.47			(33,987	)			—
Cancelled/forfeited			50.70			(5,482	)
Non-vested balance at March 31, 2015		$	24.07			567,471				1,291

Restrictions on 196,047 time-based shares will lapse in fiscal 2016. The fair value of the non-vested phantom shares at March 31, 2015 is $19.14 per unit.
Phantom stock compensation expense and grant date fair value of phantom stock vested for the years ended March 31, are as follows:


(In thousands)		2015			2014				2013
Grant date fair value of phantom stock vested		$	1,647			1,806				2,390
Phantom stock compensation expense			933			1,706				2,507
Phantom stock compensation costs capitalized as part of an asset			—			—				—
As of March 31, 2015, total unrecognized phantom stock compensation costs amounted to $13.4 million, or $10.8 million net of tax. The liability for this plan will be adjusted in the future until paid to the participant to reflect the value of the units at the respective quarter end Tidewater stock price.
Cash-based Performance Plan
The company provides a Cash-based Performance Plan as additional incentive compensation to officers of the company. The plan awards units equal to cash to participants where each unit represents the right to receive, at the end of a vesting period, up to two dollars.
Vesting of the various cash-based performance units (CBU) is based on metrics such as a three year TSR as measured against a three year TSR of a defined peer group and ROTC for the company over a three year performance period. The company uses assumptions underlying the Black-Scholes methodology to produce a Monte Carlo simulation model to value the TSR cash-based performance units. The fair value of the ROTC CBUs is based on the market price of our common stock on the date of grant less dividends associated with the ROTC component. The CBUs do not receive dividend equivalents. The restrictions on the CBU’s lapse if the company meets specific targets as defined. Upon retirement, the Compensation Committee of the Board of Directors will take into consideration the accelerated vesting of the CBUs after certain age and service criteria are met. Cash-based performance unit compensation costs are recognized on a straight-line basis over the vesting period, and are net of forfeitures.

The following table sets forth a summary of cash-based performance plan unit activity of the company for fiscal 2015:


		Weighted-average			Performance
		Grant-Date			Based
		Fair Value			Units
Non-vested balance at March 31, 2014			—			—
Granted			1.10			4,519,703
Vested			—			—
Cancelled/forfeited			—			—
Non-vested balance at March 31, 2015		$	1.10			4,519,703

No cash-based performance units outstanding at March 31, 2015 will vest during fiscal 2016.
Cash-based performance unit compensation expense and grant date fair value for the year ended March 31, is as follows:


(In thousands)		2015
Grant date fair value of cash-based performance units		$	—
Cash-based performance unit compensation expense			72
As of March 31, 2015, total unrecognized cash-based performance plan compensation costs amounted to $4.9 million, or $3.3 million net of tax. No cash-based performance plan compensation costs were capitalized as part of the costs of an asset. The amount of unrecognized cash-based performance plan compensation costs will be affected by any future cash-based unit grants and by the separation of an employee from the company who has received cash-based performance plan units that are unvested as of their separation date. There were no modifications to the cash-based performance plan units during fiscal 2015.
Non-Employee Board of Directors Deferred Stock Unit Plan
The company provides a Deferred Stock Unit Plan to its non-employee directors. The plan provides that each non-employee director is granted annually a number of stock units having an aggregate value of $115,000 beginning fiscal 2013 and $100,000 prior to fiscal 2013 on the date of grant. Dividend equivalents are paid on the stock units at the same rate as dividends on the company’s common stock and are re-invested as additional stock units based upon the fair market value of a share of company common stock on the date of payment of the dividend. A stock unit represents the right to receive from the company the equivalent value of one share of company’s common stock in cash. Payment of the value of the stock unit granted from inception of the plan to March 2013 shall be made upon the earlier of the date that is 15 days following the date the participant ceases to be a director for any reason or upon a change of control of the company. For these units, the participant can elect to receive five annual installments or a lump sum. Beginning with deferred stock units granted in fiscal 2014, participants have the additional option of electing a distribution made upon the earlier of the date that is 15 days following the date the participant ceases to be a director for any reason or upon a change of control of the company or distribution date commencing on an anniversary of the grant date, whichever is earlier. For the units granted in fiscal 2015 and 2014, the participant can elect to receive annual installments of two to ten years or a lump sum distribution.

The following table sets forth a summary of deferred stock unit activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average			Number
		Grant-Date			Of
		Fair Value			Units
Balance at March 31, 2012			50.56			114,580
Dividend equivalents reinvested			46.73			2,472
Retirement distribution			—			—
Granted			50.48			26,955
Balance at March 31, 2013			50.48			144,007
Dividend equivalents reinvested			53.82			2,492
Retirement distribution			59.65			(26,661	)
Granted			49.47			26,550
Balance at March 31, 2014		$	48.68			146,388
Dividend equivalents reinvested			34.63			3,794
Retirement distribution			47.50			(21,492	)
Granted			19.14			56,370
Balance at March 31, 2015		$	39.53			185,060

Deferred stock units are fully vested at the time of grant. The liability for this plan will be adjusted in the future until paid to the participant to reflect the value of the units at the respective quarter end Tidewater stock price.
Deferred stock unit compensation expense, which is reflected in general and administrative expenses, for the years ended March 31, are as follows:


(In thousands)		2015			2014				2013
Deferred stock units compensation expense (benefit)		$	(2,477)			1,737				1,085

Stockholders_Equity

Stockholders' Equity	12 Months Ended
Stockholders' Equity	Mar. 31, 2015
Stockholders' Equity	-9		STOCKHOLDERS’ EQUITY

	Common Stock

	The number of authorized and issued common stock and preferred stock at March 31, are as follows:



			2015				2014
	Common stock shares authorized			125,000,000				125,000,000
	Common stock par value			$0.10				$0.10
	Common stock shares issued			47,029,359				49,730,442
	Preferred stock shares authorized			3,000,000				3,000,000
	Preferred stock par value			No par				No par
	Preferred stock shares issued			—				—

	Common Stock Repurchases

	In May 2015, the company’s Board of Directors authorized an extension of its current common stock repurchase program from its original expiration date of June 30, 2015 to June 30, 2016. If shares are purchased in open market or privately-negotiated transactions pursuant to this share repurchase program, the company will use its available cash and/or borrowings under its revolving credit facility or other borrowings to fund any share repurchases. As of March 31, 2015, the company had $100 million remaining authorized under this repurchase program available to repurchase shares. The company evaluates share repurchase opportunities relative to other investment opportunities and in the context of current conditions in the credit and capital markets.

	In May 2014, the company’s Board of Directors authorized the company to spend up to $200 million to repurchase shares of its common stock in open-market or privately-negotiated transactions. The effective period for this authorization is July 1, 2014 through June 30, 2015. The company uses its available cash and, when considered advantageous, borrowings under its revolving credit facility or other borrowings, to fund any share repurchases. The company evaluates share repurchase opportunities relative to other investment opportunities and in the context of current conditions in the credit and capital markets. At March 31, 2015, $100 million remains available to repurchase shares under the May 2014 share repurchase program.



	In May 2013, the company’s Board of Directors authorized the company to spend up to $200 million to repurchase shares of its common stock in open-market or privately-negotiated transactions. The effective period for this authorization is July 1, 2013 through June 30, 2014. No shares were repurchased under the May 2013 program.

	The value of common stock repurchased, along with number of shares repurchased, and average price paid per share for the years ended March 31, are as follows:



	(In thousands, except share and per share data)		2015				2014				2013
	Aggregate cost of common stock repurchased		$	99,999				—				85,034
	Shares of common stock repurchased			2,841,976				—				1,856,900
	Average price paid per common share		$	35.19				—				45.79

	Dividend Program

	The declaration of dividends is at the discretion of the company’s Board of Directors. The Board of Directors declared the following dividends for the years ended March 31, are as follows:



	(In thousands, except per share data)		2015				2014				2013
	Dividends declared		$	49,127				49,973				49,766
	Dividend per share			1				1				1

	Accumulated Other Comprehensive Loss

	The changes in accumulated other comprehensive income by component, net of tax for the years ended March 31, are as follows:



			For the year ended March 31, 2014															For the year ended March 31, 2015
	(in thousands)		Balance				Gains/(losses)				Reclasses		Net		Remaining			Balance			Gains/(losses)			Reclasses		Net			Remaining
			at				recognized				from OCI to		period		balance			at			recognized			from OCI to		period			balance
			3/31/13				in OCI				net income		OCI		3/31/14			3/31/14			in OCI			net income		OCI			3/31/15
	Available for sale securities			(121	)			(92	)			305		213		92			92			(64	)		207		143			235
	Currency translation adjustment			(9,811	)			—				—		—		(9,811	)		(9,811	)		—			—		—			(9,811	)
	Pension/Post-retirement benefits			(4,353	)			4,237				—		4,237		(116	)		(116	)		(9,013	)		—		(9,013	)		(9,129	)
	Interest rate swap			(2,856	)			—				466		466		(2,390	)		(2,390	)		—			717		717			(1,673	)
	Total			(17,141	)			4,145				771		4,916		(12,225	)		(12,225	)		(9,077	)		924		(8,153	)		(20,378	)


	The following table summarizes the reclassifications from accumulated other comprehensive loss to the condensed consolidated statement of income for the years ended March 31,



		Year Ended								Affected line item in the condensed
		March 31,								consolidated statements of income
(In thousands)		2015				2014
Realized gains on available for sale securities		$	207				469			Interest income and other, net
Amortization of interest rate swap			717				717			Interest and other debt costs
Total pre-tax amounts			924				1,186
Tax effect			—				415
Total gains for the period, net of tax		$	924				771


Included in accumulated other comprehensive loss for the year ended March 31, 2015, is an after-tax loss of $1.8 million ($2.6 million pre-tax) relating to interest rate hedges, which are cash flow hedges, entered into in July 2010 in connection with the September 2010 senior notes offering as disclosed in Note 5. The interest rate hedges settled in August 2010 concurrent with the pricing of the senior unsecured notes. The hedges met the effectiveness criteria and will be amortized over the term of the individual notes matching the term of the hedges to interest expense.

Earnings_per_Share

Earnings per Share	12 Months Ended
Earnings per Share	Mar. 31, 2015
Earnings per Share	-10	EARNINGS PER SHARE

	The components of basic and diluted earnings per share for the years ended March 31, are as follows:



	(In thousands, except share and per share data)	2015			2014		2013

	Net earnings (loss) available to common shareholders (A)	$	(65,190	)		140,255		150,750

	Weighted average outstanding shares of common stock, basic (B)		48,658,840			49,392,749		49,550,391
	Dilutive effect of options and restricted stock awards		—			287,365		183,649
	Weighted average common stock and equivalents (C)		48,658,840			49,680,114		49,734,040

	Earnings per share, basic (A/B)	$	(1.34	)		2.84		3.04
	Earnings per share, diluted (A/C)	$	(1.34	)		2.82		3.03

	Additional information:
	Antidilutive options and restricted stock shares		284,635			34,486		82,758

SaleLeaseback_Arrangements

Sale/Leaseback Arrangements	12 Months Ended
Sale/Leaseback Arrangements	Mar. 31, 2015
Sale/Leaseback Arrangements	-11	SALE/LEASBACK ARRANGEMENTS
	Fiscal 2015 Sale/Leasebacks
	During fiscal 2015, the company sold six vessels to unrelated third parties, and simultaneously entered into bareboat charter agreements with the purchasers. Under the sale/leaseback agreements the company has the right to re-acquire the vessel for a fixed percentage of the original sales price at a defined date during the lease, deliver the vessel to the owners at the end of the lease term, purchase the vessel at its then fair market value at the end of the lease term or extend the leases for 24 months at mutually agreeable lease rates.
	The company is accounting for these transactions as sale/leasebacks with operating lease treatment and will record the payments as vessel operating lease expense on a straight-line basis over the lease term. The deferred gains will be amortized to gain on asset dispositions, net ratably over the respective lease term. Any deferred gain balance remaining upon the repurchase of the vessels would reduce the vessels’ stated cost if the company elects to exercise the purchase options.
	The following table provides the number of vessels, total proceeds, carrying values at the time of sale, deferred gains recognized, lease expirations, and contractual purchase option timing for the vessels sold and leased back by the company during fiscal 2015:


	Fiscal 2015 Quarter	Number of		Total				Carrying				Deferred		Lease	Purchase	Purchase
		Vessels		Proceeds				Value at time				Gain at time		Term	Option	Option
								of Sale				of Sale		in Years	Percentage	at end of:
	First	1		$	13,400			$	4,002			$	9,398	7	61%	6^th Year
	Second	1			19,350				8,214				11,136	8.5	47%	8^th Year
	Third	3			78,200				33,233				44,967	8 – 9	60%	7^th or 8^th Year
	Fourth	1			13,000				5,115				7,885	7	50%	6^th Year
		6		$	123,950			$	50,564			$	73,386

	Fiscal 2014 Sale/Leasebacks
	During fiscal 2014, the company sold ten vessels to unrelated third parties, and simultaneously entered into bareboat charter agreements with the purchasers. Under the sale/leaseback agreements the company has the right to re-acquire the vessel for a fixed percentage of the original sales price at a defined date during the lease, deliver the vessel to the owners at the end of the lease term, purchase the vessel at its then fair market value at the end of the lease term or extend the leases for 24 months at mutually agreeable lease rates.
	The company is accounting for these transactions as sale/leasebacks with operating lease treatment and will record the payments as vessel operating lease expense on a straight-line basis over the lease term. The deferred gains will be amortized to gain on asset dispositions, net ratably over the respective lease term. Any deferred gain balance remaining upon the repurchase of the vessels would reduce the vessels’ stated cost if the company elects to exercise the purchase options.
	The following table provides the number of vessels, total proceeds, carrying values at the time of sale, deferred gains recognized, lease expirations, and contractual purchase option timing for the vessels sold and leased back by the company during fiscal 2014:


	Fiscal 2014 Quarter	Number of		Total				Carrying				Deferred		Lease	Purchase	Purchase
		Vessels		Proceeds				Value at time				Gain at time		Term	Option	Option at
								of Sale				of Sale		in Years	Percentage	at end of:
	Second	2		$	65,550			$	34,325			$	31,225	7	55%	6^th Year
	Third	4			141,900				105,649				36,251	7 - 9	54 - 68%	6^th or 8^th Year
	Fourth	4			63,305				32,845				30,460	7 – 10	53 - 59%	6^th or 9^th Year
		10		$	270,755			$	172,819			$	97,936

	Fiscal 2010 Sale/Leaseback
	In June and July 2009, the company sold six vessels to unrelated third-party companies, and simultaneously entered into bareboat charter agreements for the vessels with the purchasers.
	The sale/leaseback transactions resulted in proceeds to the company of approximately $101.8 million and a deferred gain of $39.6 million. The aggregate carrying value of the six vessels was $62.2 million at the dates of sale. The company accounted for the transactions as sale/leaseback transactions with operating lease treatment and expenses lease payments over the five year charter hire operating lease terms.
	During the fourth quarter of fiscal 2014, the company elected to repurchase all six vessels from their respective lessors for an aggregate price of $78.8 million. Three of these were subsequently sold and leased back in March 2014. Two additional vessels were sold and leased back in April 2014 and March 2015, respectively. The carrying value of these purchased vessels has been reduced by the previously unrecognized deferred gain of $39.6 million. Refer to “Fiscal 2014 Sale/Leasebacks” above.
	Fiscal 2006 Sale/Leaseback
	In March 2006, the company entered into agreements to sell five of its vessels that were under construction at the time to an unrelated third party, for $76.5 million and simultaneously entered into bareboat charter agreements with the same unrelated third party upon the vessels’ delivery to the market. Construction on these five vessels was completed at various times between March 2006 and March 2008, at which time the company sold the respective vessels and simultaneously entered into bareboat charter agreements.
	The company accounted for all five transactions as sale/leaseback transactions with operating lease treatment. Accordingly, the company did not record the assets on its books and the company is expensing periodic lease payments. The operating lease for all five charter hire agreements were for eight year terms.
	In September 2012, the company elected to repurchase one of its leased vessels from the lessor for $8.8 million. During October 2012, the company repurchased a second leased vessel, for $8.4 million. In March 2014, the company repurchased a third and fourth leased vessel for a total cost of $22.8 million. In November 2014, the company repurchased a fifth leased vessel for a total cost of $11.2 million. Three of these vessels were sold and leased back in fiscal 2015.

	Future Minimum Lease Payments
	As of March 31, 2015, the future minimum lease payments for the vessels under the operating lease terms are as follows:


	Fiscal year ending (In thousands)	Fiscal 2015				Fiscal 2014				Total
	Fiscal year ending (In thousands)	Sale/Leaseback				Sale/Leaseback				Total
	2016		$ 9,485				20,879				30,364
	2017		9,485				20,879				30,364
	2018		9,605				23,485				33,090
	2019		10,234				24,800				35,034
	2020		11,497				25,519				37,016
	Thereafter		30,866				39,744				70,610
	Total future lease payments		$ 81,172				155,306				236,478

Commitments_and_Contingencies

Commitments and Contingencies

12 Months Ended

Mar. 31, 2015

Commitments and Contingencies

-12

COMMITMENTS AND CONTINGENCIES

Compensation Commitments

Compensation continuation agreements exist with all of the company’s officers whereby each receives compensation and benefits in the event that their employment is terminated following certain events relating to a change in control of the company. The maximum amount of cash compensation that could be paid under the agreements, based on present salary levels, is approximately $43 million.

Vessel Commitments

The table below summarizes the company’s various vessel commitments to acquire and construct new vessels, by vessel type, as of March 31, 2015:

(In thousands, except vessel count)

Number of

Total Cost

Invested

Remaining

Vessels

Through

Balance

3/31/15

Vessels under construction:

Deepwater PSVs (A)

576,847

223,301

353,546

Towing supply vessels (A)

105,804

79,297

26,507

Other

8,014

—

Total vessel commitments

690,665

310,612

380,053

(A)

In April 2015, the company cancelled the construction contracts for three towing-supply vessels. There were approximately $13 million of remaining costs to be incurred on these three vessels at the time of termination. In May 2015, the company and the Chinese shipyard that is constructing two 275-foot deepwater PSVs came to an agreement that provides the company an option to take delivery of one or both vessels at any time prior to June 30, 2016 or receive the return of installments aggregating $5.7 million per vessel at the end of this period. There were approximately $41 million of remaining costs to be incurred on these two vessels at the time of the agreement. Refer to Note (19) for a discussion of these vessel construction contract modifications.

The total cost of the various vessel new-build commitments includes contract costs and other incidental costs. The company has vessels under construction at a number of different shipyards around the world. The deepwater PSVs under construction range between 3,800 and 6,000 deadweight tons (DWT) of cargo capacity while the towing-supply/supply vessels under construction have 7,145 brake horsepower (BHP). The new-build vessels began to deliver in April 2015, with delivery of the final new-build vessel expected in September 2016.

With its commitment to modernizing its fleet through its vessel construction and acquisition program over the past decade, the company has successfully replaced the vast majority of the older vessels in its fleet with fewer, larger and more efficient vessels that have a more extensive range of capabilities. These efforts are expected to continue through the delivery of the remaining 21 vessels currently under construction, with the company anticipating that it will use some portion of its future operating cash flows and existing borrowing capacity as well as possible new borrowings or lease finance arrangements in order to fund current and future commitments in connection with the completion of the fleet renewal and modernization program.

The company is experiencing substantial delay with one fast supply boat under construction in Brazil that was originally scheduled to be delivered in September 2009. On April 5, 2011, pursuant to the vessel construction contract, the company sent the subject shipyard a letter initiating arbitration in order to resolve disputes of such matters as the shipyard’s failure to achieve payment milestones, its failure to follow the construction schedule, and its failure to timely deliver the vessel. The company has suspended construction on the vessel and both parties continue to pursue that arbitration. The company has third party credit support in the form of insurance coverage for 90% of the progress payments made on this vessel, or all but approximately $2.4 million of the carrying value of the accumulated costs through March 31, 2015. The company had committed and invested $8 million as of March 31, 2015.

In December 2013, the company took delivery of the second of two deepwater PSVs constructed in a U.S. shipyard. In connection with the delivery of those vessels, the company and the shipyard agreed to hold $11.7 million in escrow with a financial institution pending resolution of disputes over whether all or a portion of the escrowed funds were due to the shipyard as the shipyard has claimed. In October 2014, the parties resolved their pending disputes subject to a confidentiality provision and agreed on the split of the funds held in escrow. The amounts returned from the escrow to the company resulted in a reduction in the cost of the two acquired vessels, one of which was subsequently sold to an unaffiliated financial institution in connection with a sale/lease transaction that closed in the third quarter of fiscal 2014. The portion of the returned funds attributed to the vessel that was sold was recorded as a deferred gain that is being amortized over the 10-year lease term.

The company generally requires shipyards to provide third party credit support in the event that vessels are not completed and delivered timely and in accordance with the terms of the shipbuilding contracts. That third party credit support typically guarantees the return of amounts paid by the company and generally takes the form of refundment guarantees or standby letters of credit issued by major financial institutions generally located in the country of the shipyard. While the company seeks to minimize its shipyard credit risk by requiring these instruments, the ultimate return of amounts paid by the company in the event of shipyard default is still subject to the creditworthiness of the shipyard and the provider of the credit support, as well as the company’s ability to successfully pursue legal action to compel payment of these instruments. When third party credit support that is acceptable to the company is not available or cost effective, the company endeavors to limit its credit risk by minimizing pre-delivery payments and through other contract terms with the shipyard.

Merchant Navy Officers Pension Fund

On July 15, 2013, a subsidiary of the company was placed into administration in the United Kingdom. Joint administrators were appointed to administer and distribute the subsidiary’s assets to the subsidiary’s creditors. The vessels owned by the subsidiary had become aged and were no longer economical to operate, which has caused the subsidiary’s main business to decline in recent years. Only one vessel generated revenue as of the date of the administration. As part of the administration, the company agreed to acquire seven vessels from the subsidiary (in exchange for cash) and to waive certain intercompany claims. The purchase price valuation for the vessels, all but one of which were stacked, was based on independent, third party appraisals of the vessels.

The company previously reported that a subsidiary of the company is a participating employer in an industry-wide multi-employer retirement fund in the United Kingdom, known as the Merchant Navy Officers Pension Fund (MNOPF). The subsidiary that participates in the MNOPF is the entity that was placed into administration in the U.K. The MNOPF is that subsidiary’s largest creditor, and has claimed as an unsecured creditor in the administration. The Company believed that the administration was in the best interests of the subsidiary and its principal stakeholders, including the MNOPF. The MNOPF indicated that it did not object to the insolvency process and that, aside from asserting its claim in the subsidiary’s administration and based on the company’s representations of the financial status and other relevant aspects of the subsidiary, the MNOPF will not pursue the subsidiary in connection with any amounts due or which may become due to the fund.

In December 2013, the administration was converted to a liquidation. That conversion allowed for an interim cash liquidation distribution to be made to the MNOPF. The conversion is not expected to have any impact on the company and the liquidation is expected to be completed in calendar 2015. The company believes that the liquidation will resolve the subsidiary’s participation in the MNOPF. The company also believes that the ultimate resolution of this matter will not have a material effect on the consolidated financial statements.

Sonatide Joint Venture

As previously reported, in November 2013, a subsidiary of the company and its joint venture partner in Angola, Sonangol Holdings Lda. (“Sonangol”), executed a new joint venture agreement for their joint venture, Sonatide. The new joint venture agreement is currently effective and will expire, unless extended, two years after an Angolan entity, which is intended to be one of the Sonatide group of companies, has been incorporated. The Angolan entity is expected to be incorporated by late 2015 after certain Angolan regulatory approvals have been obtained.

The challenges for the company to successfully operate in Angola remain significant. As the company has previously reported, on July 1, 2013, elements of new legislation (the “forex law”) became effective that generally require oil companies that engage in exploration and production activities offshore Angola through governmental concessions to pay for goods and services provided by foreign exchange residents in Angolan kwanzas that are initially deposited into an Angolan bank account. The forex law also imposes documentation and other requirements on service companies such as Sonatide in order to effect payments that are denominated in currencies other than Angolan kwanzas. The forex law has resulted in, and will likely continue to result in, substantial customer payments being made to Sonatide in Angolan kwanzas. This cumbersome payment process has imposed and could continue to impose a burden on Tidewater’s management of its cash and liquidity, because of the risks that the conversion of Angolan kwanzas into U.S. dollars and the subsequent expatriation of the funds could result in payment delays and currency devaluation prior to conversion of kwanzas to dollars, as well as burden the company with additional operating costs to convert kwanzas into dollars and potentially additional taxes.

In response to the new forex law, Tidewater and Sonangol negotiated and signed an agreement that is set to expire, unless extended, in November 2015 (the “consortium agreement”) that is intended to allow the Sonatide joint venture to enter into contracts with customers that allocate billings for services provided by Sonatide between (i) billings for local services that are provided by a foreign exchange resident (that must be paid in kwanzas), and (ii) billings for services provided by offshore residents (that can be paid in dollars). Sonatide successfully converted select customer contracts to this split billing arrangement during the quarter ended March 31, 2015 and continues to discuss this type of billing arrangement with other customers. We are unable to determine the impact that an inability to extend the consortium agreement would have on the existing split billing arrangements, and the ability to enter into new split billing arrangements. In addition, it is not clear if this type of contracting will be available to Sonatide over the longer term.

In November 2014, the National Bank of Angola issued new regulations controlling the sale of foreign currency. These regulations generally require oil companies to sell U.S. dollars to the National Bank of Angola to buy kwanzas that are required to be used to pay for goods and services provided by foreign exchange resident oilfield service companies. These foreign exchange resident oilfield service companies, in turn, are required to source U.S. dollars in order to pay for goods and services provided offshore. The regulations continue to permit tripartite agreements among oil companies, commercial banks and service companies that provide for the sale of U.S. dollars by an oil company to a commercial bank in exchange for kwanzas. These same U.S. dollars are then sold onward by the commercial bank to the service company. The implementing regulations do, however, place constraints on those tripartite agreements that did not previously exist, and the period of time that the tripartite agreements will be allowed remains uncertain. If tripartite agreements or similar arrangements are not available to service companies in Angola that have a need for dollars, then such service companies will be required to source dollars exclusively through the National Bank of Angola. Sonatide has had limited success to date negotiating tripartite agreements but it continues its discussions with customers, commercial banks and the National Bank of Angola regarding these arrangements.

For the fiscal year ended March 31, 2015, the company collected (primarily through Sonatide) approximately $338 million from its Angola operations, which is slightly less than the approximately $351 million of revenue recognized for the same period. Of the $338 million collected approximately $159 million represented U.S. dollars received by Sonatide on behalf of the company or dollars directly received by the company from customers. The balance of $179 million collected resulted from Sonatide’s converting kwanza into dollars and subsequently expatriating the dollars to Tidewater. Additionally, the company received an approximate $10 million dividend payment from the Sonatide joint venture during the third quarter of fiscal 2015.

Though Sonatide experienced a substantially reduced ability to convert kwanzas to dollars during parts of the quarter ended December 31, 2014 (possibly due to holiday season and/or the newly enhanced role of the National Bank of Angola from November 2014 in the conversion process), the company believes that the process for converting kwanzas has functioned reasonably well for much of fiscal 2015, particularly given that the conversion process was still developing. Sonatide continues to press its commercial bank relationships to increase the amount of dollars that are made available to Sonatide.

As of March 31, 2015, the company had approximately $420 million in amounts due from Sonatide, with approximately half of the balance reflecting invoiced but unpaid vessel revenue related to services performed by the company through the Sonatide joint venture. Remaining amounts due to the company from Sonatide generally reflect cash (primarily denominated in Angolan kwanzas) held by Sonatide that is pending conversion into U.S. dollars and the subsequent expatriation of such funds. Cash held by Sonatide began to accumulate in late calendar 2012, when the initial provisions of the forex law relating to payments for goods and services provided by foreign exchange residents took effect (and payments were required to be paid into local bank accounts). Beginning in July 2013, when the second provision of the forex law took effect (and the local payments had to be made in kwanza), Sonatide generally accrued for but did not deliver invoices to customers for vessel revenue related to Sonatide and the company’s collective Angolan operations in order to minimize the exposure that Sonatide would be paid for a substantial amount of charter hire in kwanzas and into an Angolan bank. During this time, the company began using its credit facility and other arrangements to fund the substantial working capital requirements related to its Angola operations.

Beginning in the first quarter of fiscal 2015, Sonatide began sending invoices to those customers that insisted on paying U.S. dollar denominated invoices in kwanza. As invoices are paid in kwanza, Sonatide seeks to convert those kwanzas into U.S. dollars and subsequently utilize those U.S. dollars to pay the amounts that Sonatide owes the company. This conversion and expatriation process is subject to those risks and considerations set forth above.

For the fiscal year ended March 31, 2015, Tidewater’s Angolan operations generated vessel revenues of approximately $351 million, or 23%, of its consolidated vessel revenue, from an average of approximately 80 Tidewater-owned vessels that are marketed through the Sonatide joint venture (8 of which were stacked on average during the year ended March 31, 2015), and, for the year ended March 31, 2014, generated vessel revenues of approximately $357 million, or 25%, of consolidated vessel revenue, from an average of approximately 90 Tidewater-owned vessels (five of which were stacked on average during the year ended March 31, 2014).

Sonatide joint venture owns nine vessels (three of which are currently stacked) and certain other assets, in addition to earning commission income from Tidewater-owned vessels marketed through the Sonatide joint venture (owned 49% by Tidewater). In addition, as of March 31, 2015, Sonatide maintained the equivalent of approximately $150 million of kwanza-denominated deposits in Angolan banks, largely related to customer receipts that had not yet been converted to U.S. dollars, expatriated and then remitted to the company. As of March 31, 2015 and March 31, 2014, the carrying value of Tidewater’s investment in the Sonatide joint venture, which is included in “Investments in, at equity, and advances to unconsolidated companies,” is approximately $67 million and $62 million, respectively.

Due from affiliate at March 31, 2015 and March 31, 2014 of approximately $420 million and $430 million, respectively, represents cash received by Sonatide from customers and due to the company, amounts due from customers that are expected to be remitted to the company through Sonatide and, finally, reimbursable costs paid by Tidewater on behalf of Sonatide. The collection of the amounts due from customers and the subsequent conversion and expatriation process are subject to those risks and considerations set forth above.

Due to affiliate at March 31, 2015 and March 31, 2014 of approximately $186 million and $86 million, respectively, represents amounts due to Sonatide for commissions payable (approximately $66 million and $43 million, respectively) and other costs paid by Sonatide on behalf of the company.

A new presidential decree regulating maritime transportation activities was enacted in Angola earlier this year. Following recent discussions with port state authorities and local counsel, the company is uncertain whether the authorities will interpret the decree to require one hundred percent Angolan ownership of local vessel operators such as Sonatide. This interpretation may result in the need to work with Sonangol to further restructure our Sonatide joint venture and our operations in Angola. The company has been informed by the authorities that the deadline for foreign vessel operators to comply with any rules implementing the decree has been set for June 2015. The company is seeking further clarification of the new decree and has been advised that a grace period for compliance will be granted until such clarifications are published. The company is exploring potential alternative structures in order to comply.

The Angolan government has included a proposal for a new levy in its most recent budget that could impose an additional 10-20% surcharge on foreign exchange transactions. We understand that a new decree imposing a levy could be published soon. The specific details of the levy have not yet been disclosed and it is not clear if this new decree would apply to Sonatide’s scope of operations. The company has undertaken efforts to mitigate the effects of the levy, in the event the levy is enacted into law, including successfully negotiating rate adjustments and termination rights with some of its customers. The company will be unlikely to completely mitigate the effects of the levy, resulting in increased costs and lower margins, if the levy is enacted.

Management continues to explore ways to profitably participate in the Angolan market while looking for opportunities to reduce the overall level of exposure to the increased risks that the company believes currently characterize the Angolan market. Included among mitigating measures taken by the company to address these risks is the redeployment of vessels from time to time to other markets where there is adequate demand for the company’s vessels. During the year ended March 31, 2014, the company redeployed vessels from its Angolan operations to other markets and also transferred vessels into its Angolan operations from other markets resulting in a net increase of one vessel operating in Angola. Redeployment of vessels to and from Angola in the year ended March 31, 2015 has resulted in a net 13 vessels transferred out of Angola, including four smaller crewboats that were stacked outside of Angola.

As the company considers the redeployment of additional vessels from Angola to other markets, there would likely be temporary negative financial effects associated with such redeployment, including mobilization costs and costs to redeploy Tidewater shore-based employees to other areas, in addition to lost revenues associated with potential downtime between vessel contracts. These financial impacts could, individually or in the aggregate, be material to our results of operations and cash flows for the periods when such costs would be incurred. The recent decline in crude oil and natural gas prices, the reduction in spending expectations among E&P companies, the number of new-build vessels which are expected to deliver within the next two years and the resulting potential overcapacity in the worldwide offshore support vessel market may exacerbate such negative financial effects, particularly if a large re-deployment were undertaken by the company in the near- to intermediate-term.

Brazilian Customs

In April 2011, two Brazilian subsidiaries of Tidewater were notified by the Customs Office in Macae, Brazil that they were jointly and severally being assessed fines of 155 million Brazilian reais (approximately $48.5 million as of March 31, 2015). The assessment of these fines is for the alleged failure of these subsidiaries to obtain import licenses with respect to 17 Tidewater vessels that provided Brazilian offshore vessel services to Petrobras, the Brazilian national oil company, over a three-year period ending December 2009. After consultation with its Brazilian tax advisors, Tidewater and its Brazilian subsidiaries believe that vessels that provide services under contract to the Brazilian offshore oil and gas industry are deemed, under applicable law and regulations, to be temporarily imported into Brazil, and thus exempt from the import license requirement. The Macae Customs Office has, without a change in the underlying applicable law or regulations, taken the position that the temporary importation exemption is only available to new, and not used, goods imported into Brazil and therefore it was improper for the company to deem its vessels as being temporarily imported. The fines have been assessed based on this new interpretation of Brazilian customs law taken by the Macae Customs Office.

After consultation with its Brazilian tax advisors, the company believes that the assessment is without legal justification and that the Macae Customs Office has misinterpreted applicable Brazilian law on duties and customs. The company is vigorously contesting these fines (which it has neither paid nor accrued) and, based on the advice of its Brazilian counsel, believes that it has a high probability of success with respect to the overturn of the entire amount of the fines, either at the administrative appeal level or, if necessary, in Brazilian courts. In December 2011, an administrative board issued a decision that disallowed 149 million Brazilian reais (approximately $46.6 million as of March 31, 2015) of the total fines sought by the Macae Customs Office. In two separate proceedings in 2013, a secondary administrative appeals board considered fines totaling 127 million Brazilian reais (approximately $39.7 million as of March 31, 2015) and rendered decisions that disallowed all of those fines. The remaining fines totaling 28 million Brazilian reais (approximately $8.8 million as of March 31, 2015) are still subject to a secondary administrative appeals board hearing, but the company believes that both decisions will be helpful in that upcoming hearing. The secondary board decisions disallowing the fines totaling 127 million Brazilian reais are, however, still subject to the possibility of further administrative appeal by the authorities that imposed the initial fines. The company believes that the ultimate resolution of this matter will not have a material effect on the consolidated financial statements.

Nigeria Marketing Agent Litigation

On March 1, 2013, Tidewater filed suit in the London Commercial Court against Tidewater’s Nigerian marketing agent for breach of the agent’s obligations under contractual agreements between the parties. The alleged breach involves actions of the Nigerian marketing agent to discourage various affiliates of TOTAL S.A. from paying approximately $16 million (including U.S. dollar denominated invoices and Naira denominated invoices which have been adjusted for the devaluation of the Naira relative to the U.S. dollar) due to the company for vessel services performed in Nigeria. Shortly after the London Commercial Court filing, TOTAL commenced interpleader proceedings in Nigeria naming the Nigerian agent and the company as respondents and seeking an order which would allow TOTAL to deposit those monies with a Nigerian court for the respondents to resolve. On April 25, 2013, Tidewater filed motions in the Nigerian Federal High Court to stop the interpleader proceedings in Nigeria or alternatively stay them until the resolution of the suit filed in London. The company will continue to actively pursue the collection of those monies. On April 30, 2013, the Nigerian marketing agent filed a separate suit in the Nigerian Federal High Court naming Tidewater and certain TOTAL affiliates as defendants. The suit seeks various declarations and orders, including a claim for the monies that are subject to the above interpleader proceedings, and other relief. The company is seeking dismissal of this suit and otherwise intends to vigorously defend against the claims made. The company has not reserved for this receivable and believes that the ultimate resolution of this matter will not have a material effect on the consolidated financial statements. On or about December 30, 2014, the company received notice that the Nigerian marketing agent had filed an action in the Nigerian Federal High court seeking to prevent the continuation of the proceedings initiated by Tidewater in the London Commercial Court. The company intends to vigorously defend that action.

In October, 2012, Tidewater had notified the Nigerian marketing agent that it was discontinuing its relationship with the Nigerian marketing agent. The company has entered into a new strategic relationship with a different Nigerian counterparty that it believes will better serve the company’s long term interests in Nigeria. This new strategic relationship is currently functioning as the company intended.

Arbitral Award for the Taking of the Company’s Venezuelan Operations

On March 13, 2015, the three member tribunal constituted under the rules of the World Bank’s International Centre for the Settlement of Investment Disputes (“ICSID”) has awarded subsidiaries of the company more than $62 million in compensation, including accrued interest and costs, for the Bolivarian Republic of Venezuela’s (“Venezuela”) expropriation of the investments of those subsidiaries in Venezuela. The award, issued in accordance with the provisions of the Venezuela-Barbados Bilateral Investment Treaty (“BIT”), represented $46.4 million for the fair market value of the company’s principal Venezuelan operating subsidiary, plus interest from May 8, 2009 to the date of payment of that amount accruing at an annual rate of 4.5% compounded quarterly ($13.9 million as of March 13, 2015) and $2.5 million for reimbursement of legal and other costs expended by the company in connection with the arbitration.

As previously reported by the company, on February 16, 2010, Tidewater and certain of its subsidiaries (collectively, the “Claimants”) filed with ICSID a Request for Arbitration against Venezuela. In May 2009, Petróleos de Venezuela, S.A. (“PDVSA”), the national oil company of Venezuela, took possession and control of (a) eleven of the Claimants’ vessels that were then supporting PDVSA operations in Lake Maracaibo, (b) the Claimants’ shore-based headquarters adjacent to Lake Maracaibo, (c) the Claimants’ operations in Lake Maracaibo, and (d) certain other related assets. In July 2009, Petrosucre, S.A., a subsidiary of PDVSA, took possession and control of the Claimants’ four vessels, operations, and related assets in the Gulf of Paria. It was Tidewater’s position that, through those measures, Venezuela directly or indirectly expropriated the Claimants’ Venezuela investments, including the capital stock of the Claimants’ principal operating subsidiary in Venezuela. As a result of the seizures, the lack of further operations in Venezuela, and the continuing uncertainty about the timing and amount of the compensation the company might collect in the future, the company recorded a charge during the year ended March 31, 2010 to write off substantially all of the assets associated with the company’s Venezuelan operations.

The Claimants alleged in the Request for Arbitration that the measures taken by Venezuela against the Claimants violated Venezuela’s obligations under the BIT and rules and principles of Venezuelan law and international law. In the first phase of the case, the tribunal addressed Venezuela’s objections to the tribunal’s jurisdiction over the dispute. On February 8, 2013, the tribunal issued its decision on jurisdiction and found that it had jurisdiction over the claims under the BIT, including the claim for compensation for the expropriation of Tidewater’s principal operating subsidiary, but that it did not have jurisdiction based on Venezuela’s investment law. The practical effect of the tribunal’s decision was to exclude from the ICSID arbitration proceeding the Claimants’ claims for expropriation of the fifteen vessels described above. While the tribunal determined that it did not have jurisdiction over the claim for the seizure of the fifteen vessels, Tidewater received during fiscal 2011 insurance proceeds for the insured value of those vessels (less an additional premium payment triggered by those proceeds).

The company will take appropriate steps to enforce and collect the award, which is enforceable in any of the 150 member states that are party to the ICSID Convention. As an initial step, the company was successful in having the award recognized and entered on March 16, 2015 as a final judgment by the United States District Court for the Southern District of New York. The Company notes that Venezuela may seek annulment of the award and other post-award relief under the ICSID Convention and may seek a stay of enforcement of the award while those post-award remedial proceedings are pending. Even in the absence of a stay of enforcement, the company recognizes that collection of the award may present significant practical challenges, particularly in the short term. Because the award has yet to be satisfied and post-award relief may be sought by Venezuela, the net impact of these matters on the company cannot be reasonably estimated at this time and the company has not recognized a gain related to these matters as of March 31, 2015.

Repairs to U.S. Flagged Vessels Operating Abroad

The company recently became aware that we may not have been following all applicable laws and regulations in documenting and declaring upon re-entry to U.S. waters all repairs done on our U.S. flagged vessels while they were working outside the United States. When a U.S. flagged vessel operates abroad, any repairs made abroad must be declared to U.S. Customs. Duties must be paid for certain of those repairs upon return to U.S. waters. During our examination of our most recent filings with U.S. Customs, we determined that it was necessary to file amended forms with U.S. Customs. We continue to evaluate the return of other U.S. flagged vessels to the United States to determine whether it is necessary to adjust our responses in any of those instances. To the extent that further evaluation requires us to file amended entries, we do not yet know the magnitude of any duties, fines or interest associated with amending the entries for these vessels. We are committed to bolstering our processes, procedures and training to ensure that we correctly identify all repairs made abroad if and when U.S. flagged vessels return to the United States in the future.

Currency Devaluation and Fluctuation Risk

Due to the company’s global operations, the company is exposed to foreign currency exchange rate fluctuations and exchange rate risks on all charter hire contracts denominated in foreign currencies. For some of our non-U.S. contracts, a portion of the revenue and local expenses are incurred in local currencies with the result that the company is at risk of changes in the exchange rates between the U.S. dollar and foreign currencies. We generally do not hedge against any foreign currency rate fluctuations associated with foreign currency contracts that arise in the normal course of business, which exposes us to the risk of exchange rate losses. To minimize the financial impact of these items, the company attempts to contract a significant majority of its services in U.S. dollars. In addition, the company attempts to minimize its financial impact of these risks, by matching the currency of the company’s operating costs with the currency of the revenue streams when considered appropriate. The company continually monitors the currency exchange risks associated with all contracts not denominated in U.S. dollars. Discussions related to the company’s Angolan operations are disclosed in Note (12) of Notes to Consolidated Financial Statements included in Item 8 of this Annual Report on Form 10-K.

Legal Proceedings

Various legal proceedings and claims are outstanding which arose in the ordinary course of business. In the opinion of management, the amount of ultimate liability, if any, with respect to these actions, will not have a material adverse effect on the company’s financial position, results of operations, or cash flows.

Fair_Value_Measurements_and_Di

Fair Value Measurements and Disclosures

12 Months Ended

Mar. 31, 2015

Fair Value Measurements and Disclosures

-13

FAIR VALUE MEASUREMENTS AND DISCLOSURES

Assets and Liabilities Measured at Fair Value on a Recurring Basis

Other Financial Instruments

The company’s primary financial instruments consist of cash and cash equivalents, trade receivables and trade payables with book values that are considered to be representative of their respective fair values. The company periodically utilizes derivative financial instruments to hedge against foreign currency denominated assets and liabilities, currency commitments, or to lock in desired interest rates. These transactions are generally spot or forward currency contracts or interest rate swaps that are entered into with major financial institutions. Derivative financial instruments are intended to reduce the company’s exposure to foreign currency exchange risk and interest rate risk. The company enters into derivative instruments only to the extent considered necessary to address its risk management objectives and does not use derivative contracts for speculative purposes. The derivative instruments are recorded at fair value using quoted prices and quotes obtainable from the counterparties to the derivative instruments.

Cash Equivalents. The company’s cash equivalents, which are securities with maturities less than 90 days, are held in money market funds or time deposit accounts with highly rated financial institutions. The carrying value for cash equivalents is considered to be representative of its fair value due to the short duration and conservative nature of the cash equivalent investment portfolio.

Spot Derivatives. Spot derivative financial instruments are short-term in nature and generally settle within two business days. The fair value of spot derivatives approximates the carrying value due to the short-term nature of this instrument, and as a result, no gains or losses are recognized.

The company had two foreign exchange spot contracts outstanding at March 31, 2015, which had a notional value of $2.3 million. The spot contracts settled by April 1, 2015. The company had four foreign exchange spot contracts outstanding at March 31, 2014, which had a notional value of $2.3 million. The spot contracts settled by April 2, 2014.

Forward Derivatives. Forward derivative financial instruments are generally longer-term in nature but generally do not exceed one year. The accounting for gains or losses on forward contracts is dependent on the nature of the risk being hedged and the effectiveness of the hedge. Forward contracts are valued using counterparty quotations, and we validate the information obtained from the counterparties in calculating the ultimate fair values using the market approach and obtaining broker quotations. As such, these derivative contracts are classified as Level 2.

At March 31, 2015, and 2014 the company did not have any forward contracts outstanding.

The following table provides the fair value hierarchy for the company’s other financial instruments measured as of March 31, 2015:

(In thousands)

Total

Quoted prices in

Significant

active markets

observable

unobservable

(Level 1)

inputs

(Level 2)

(Level 3)

Money market cash equivalents

3,007

—

Total fair value of assets

3,007

—

The following table provides the fair value hierarchy for the company’s other financial instruments measured as of March 31, 2014:

(In thousands)

Total

Quoted prices in

Significant

active markets

observable

unobservable

(Level 1)

inputs

(Level 2)

(Level 3)

Money market cash equivalents

16,559

—

Total fair value of assets

16,559

—

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

Asset Impairments

The company accounts for long-lived assets in accordance with ASC 360-10-35, Impairment or Disposal of Long-Lived Assets. The company reviews the vessels in its active fleet for impairment whenever events occur or changes in circumstances indicate that the carrying amount of an asset group may not be recoverable. In such evaluation the estimated future undiscounted cash flows generated by an asset group are compared with the carrying amount of the asset group to determine if a write-down may be required. Active, non-stacked vessels are grouped together for impairment testing purposes with vessels of similar operating and marketing characteristics. Active vessel groupings are also subdivided between older vessels and newer vessels.

The company estimates cash flows based upon historical data adjusted for the company’s best estimate of expected future market performance, which, in turn, is based on industry trends. If an asset group fails the undiscounted cash flow test, the company uses the discounted cash flow method to determine the estimated fair value of each asset group and compares such estimated fair value (considered Level 3, as defined by ASC 360) to the carrying value of each asset group in order to determine if impairment exists. If impairment exists, the carrying value of the asset group is reduced to its estimated fair value.

In addition to the periodic review of its active long-lived assets for impairment when circumstances warrant, the company also performs a review of its stacked vessels and vessels withdrawn from service every six months or whenever changes in circumstances indicate that the carrying amount of a vessel may not be recoverable. Management estimates each stacked vessel’s fair value by considering items such as the vessel’s age, length of time stacked, likelihood of a return to active service, actual recent sales of similar vessels, which are unobservable inputs. In certain situations we obtain an estimate of the fair value of the stacked vessel from third-party appraisers or brokers. The company records an impairment charge when the carrying value of a vessel withdrawn from service or a stacked vessel exceeds its estimated fair value. The estimates of fair value of stacked vessels are also subject to significant variability, are sensitive to changes in market conditions, and are reasonably likely to change in the future.

The below table summarizes the combined fair value of the assets that incurred impairments along with the amount of impairment during the years ended March 31. The fair values of impaired assets are based on expected net proceeds from asset sales or appraisals performed by third parties. The impairment charges were recorded in gain on asset dispositions, net.

(In thousands)

2015

2014

2013

Amount of impairment incurred

14,525

9,341

8,078

Combined fair value of assets incurring impairment

28,509

11,149

14,733

Gain_on_Disposition_of_Assets_

Gain on Disposition of Assets, Net	12 Months Ended
Gain on Disposition of Assets, Net	Mar. 31, 2015
Gain on Disposition of Assets, Net	-14	GAIN ON DISPOSITION OF ASSETS, NET
	The company seeks opportunities to dispose its older vessels when market conditions warrant and opportunities arise. As such, vessel dispositions vary from year to year, and gains on sales of assets may also fluctuate significantly from period to period. The majority of the company’s vessels are sold to buyers who do not compete with the company in the offshore energy industry.

	The number of vessels disposed along with the gain on the dispositions for the years ended March 31, are as follows:


	(In thousands, except number of vessels disposed)	2015		2014		2013
	Gain on vessels disposed	$	2,988		12,247		12,191
	Number of vessels disposed		13		48		32
	Also included in gain on dispositions of assets, net in fiscal 2015 are amortized gains on sale/leaseback transactions of $17.7 million as well as a gain related to the reversal of an accrued $3 million liability related to contingent consideration potentially payable to the former owners of Troms Offshore based on the achievement by the Troms operation of certain performance metrics subsequent to its acquisition by the company. The company’s current expectation is that such performance metrics will not be achieved. Included in gain on dispositions of assets, net in fiscal 2014 and fiscal 2013 are gains of $4 million and $2.3 million, respectively related to the sale of the company’s two shipyards. Please refer to Note (13) above for a discussion on asset impairment.

Segment_Information_Geographic

Segment Information, Geographical Data and Major Customers	12 Months Ended
Segment Information, Geographical Data and Major Customers	Mar. 31, 2015
Segment Information, Geographical Data and Major Customers	-15		SEGMENT INFORMATION, GEOGRAPHICAL DATA AND MAJOR CUSTOMERS

	The company follows the disclosure requirements of ASC 280, Segment Reporting. Operating business segments are defined as a component of an enterprise for which separate financial information is available and is evaluated by the chief operating decision maker in deciding how to allocate resources and in assessing performance.

	We manage and measure our business performance in four distinct operating segments: Americas, Asia/Pacific, Middle East/North Africa, and Sub-Saharan Africa/Europe. These segments are reflective of how the company’s chief operating decision maker (CODM) reviews operating results for the purposes of allocating resources and assessing performance. The company’s CODM is its Chief Executive Officer.



	The following table provides a comparison of revenues, vessel operating profit, depreciation and amortization, and additions to properties and equipment for the years ended March 31. Vessel revenues and operating costs relate to vessels owned and operated by the company while other operating revenues relate to the activities of the company’s shipyards, brokered vessels and other miscellaneous marine-related businesses.



	(In thousands)		2015				2014				2013
	Revenues:
	Vessel revenues:
	Americas		$	505,699				410,731				327,059
	Asia/Pacific			150,820				154,618				184,014
	Middle East/North Africa			205,787				186,524				149,412
	Sub-Saharan Africa/Europe			606,052				666,588				569,513
				1,468,358				1,418,461				1,229,998
	Other operating revenues			27,159				16,642				14,167
			$	1,495,517				1,435,103				1,244,165

	Vessel operating profit:
	Americas		$	122,988				90,936				40,318
	Asia/Pacific			11,541				29,044				43,704
	Middle East/North Africa			37,258				42,736				39,069
	Sub-Saharan Africa/Europe			122,169				136,092				129,460
				293,956				298,808				252,551
	Other operating loss			(8,022	)			(1,930	)			(833	)
				285,934				296,878				251,718

	Corporate general and administrative expenses (A)			(40,621	)			(47,703	)			(48,704	)
	Corporate depreciation			(4,014	)			(3,073	)			(3,391	)
	Corporate expenses			(44,635	)			(50,776	)			(52,095	)

	Gain on asset dispositions, net			9,271				11,722				6,609
	Goodwill impairment			(283,699	)			(56,283	)			—
	Restructuring charge			(4,052	)			—				—
	Operating income (loss)			(37,181	)			201,541				206,232
	Foreign exchange gain			8,678				1,541				3,011
	Equity in net earnings of unconsolidated companies			10,179				15,801				12,189
	Interest income and other, net			1,927				2,123				3,476
	Loss on early extinguishment of debt			—				(4,144	)			—
	Interest and other debt costs			(50,029	)			(43,814	)			(29,745	)
	Earnings (loss) before income taxes		$	(66,426	)			173,048				195,163

	Depreciation and amortization:
	Americas		$	47,682				43,298				40,454
	Asia/Pacific			18,383				17,174				19,416
	Middle East/North Africa			27,538				24,441				18,784
	Sub-Saharan Africa/Europe			73,614				79,199				65,241
				167,217				164,112				143,895
	Other			3,973				295				13
	Corporate			4,014				3,073				3,391
			$	175,204				167,480				147,299

	Additions to properties and equipment:
	Americas		$	94,137				99,798				52,299
	Asia/Pacific			91,497				2,586				19,858
	Middle East/North Africa			1,842				8,042				3,833
	Sub-Saharan Africa/Europe (B)			36,105				488,984				197,534
				223,581				599,410				273,524
	Other			18,571				31,841				—
Corporate (C)			124,411				175,233				179,058
		$	366,563				806,484				452,582

Total assets (D):
Americas		$	1,016,133				1,017,736				880,368
Asia/Pacific			506,265				421,379				607,546
Middle East/North Africa			666,983				613,303				507,124
Sub-Saharan Africa/Europe			2,064,010				2,383,507				1,706,355
			4,253,391				4,435,925				3,701,393
Other			49,554				31,545				5,102
			4,302,945				4,467,470				3,706,495
Investments in and advances to unconsolidated companies			65,844				63,928				46,047
			4,368,789				4,531,398				3,752,542
Corporate (E)			387,373				354,431				415,513
		$	4,756,162				4,885,829				4,168,055



(A)	Included in Corporate general and administrative expenses for the year ended March 31, 2014 and 2013 are transaction costs of $3.7 million related to the acquisition of Troms Offshore and a settlement charge of $5.2 million related to the payment of retirement benefits to a former Chief Executive Officer, respectively.


(B)	Included in Sub-Saharan Africa/Europe for the year ended March 31, 2014 is $245.6 million related to vessels acquired through the acquisition of Troms Offshore.


(C)	Included in Corporate are additions to properties and equipment relating to vessels currently under construction which have not yet been assigned to a non-corporate reporting segment as of the dates presented.


(D)	Marine support services are conducted worldwide with assets that are highly mobile. Revenues are principally derived from offshore service vessels, which regularly and routinely move from one operating area to another, often to and from offshore operating areas in different continents. Because of this asset mobility, revenues and long-lived assets attributable to the company’s international marine operations in any one country are not material.


(E)	Included in Corporate are vessels currently under construction which have not yet been assigned to a non-corporate reporting segment. The vessel construction costs will be reported in Corporate until the earlier of the vessels being assigned to a non-corporate reporting segment or the vessels’ delivery. At March 31, 2015, 2014 and 2013, $235.2 million, $228.9 million and $229.3 million, respectively, of vessel construction costs are included in Corporate.

The following table discloses the amount of revenue by segment, and in total for the worldwide fleet, along with the respective percentage of total vessel revenue for the years ended March 31,:



Revenue by vessel class:		2015				% of Vessel				2014				% of Vessel			2013		% of Vessel
(In thousands):		2015				Revenue				2014				Revenue			2013		Revenue
Americas fleet:
Deepwater		$	353,232				24	%			263,750				18	%		179,032		15	%
Towing-supply			125,029				9	%			115,055				8	%		120,817		10	%
Other			27,438				2	%			31,926				3	%		27,210		2	%
Total		$	505,699				35	%			410,731				29	%		327,059		27	%
Asia/Pacific fleet:
Deepwater		$	94,538				6	%			88,191				6	%		96,118		8	%
Towing-supply			53,281				4	%			62,630				5	%		84,217		7	%
Other			3,001				<1	%			3,797				<1	%		3,679		<1	%
Total		$	150,820				10	%			154,618				11	%		184,014		15	%
Middle East/North Africa fleet:
Deepwater		$	85,279				6	%			66,503				5	%		55,945		5	%
Towing-supply			117,232				8	%			116,720				8	%		89,902		7	%
Other			3,276				<1	%			3,301				<1	%		3,565		<1	%
Total		$	205,787				14	%			186,524				13	%		149,412		12	%
Sub-Saharan Africa/Europe fleet:
Deepwater		$	326,315				22	%			364,722				26	%		273,544		22	%
Towing-supply			208,324				14	%			231,224				16	%		226,357		18	%
Other			71,413				5	%			70,642				5	%		69,612		6	%
Total		$	606,052				41	%			666,588				47	%		569,513		46	%
Worldwide fleet:
Deepwater		$	859,364				58	%			783,166				55	%		604,639		50	%
Towing-supply			503,866				35	%			525,629				37	%		521,293		42	%
Other			105,128				7	%			109,666				8	%		104,066		8	%
Total		$	1,468,358				100	%			1,418,461				100	%		1,229,998		100	%


The following table discloses our customers that accounted for 10% or more of total revenues during the years ended March 31:



		2015				2014				2013
Chevron Corporation			12.7	%			18.1	%			17.8	%
Petroleo Brasileiro SA			11.8	%			8.6	%			8.6	%
BP plc			10.1	%			8.9	%			7.9	%

Goodwill

Goodwill	12 Months Ended
Goodwill	Mar. 31, 2015
Goodwill	-16		GOODWILL
	The company tests goodwill for impairment annually at the reporting unit level using carrying amounts as of December 31 or more frequently if events and circumstances indicate that goodwill might be impaired.
	During the quarter ended December, 31, 2014 the company performed its annual goodwill impairment assessment and determined that the rapid and significant decline in crude oil and natural gas prices (which occurred and accelerated throughout the latter part of the company’s third fiscal quarter), and the expected short to intermediate term effect that the downturn might have on levels of exploration and production activity would likely have a negative effect on average day rates and utilization levels of the company’s vessels. Expected future cash flow analyses using the projected average day rates and utilization levels in this new commodity pricing environment were included in the company’s valuation models and indicated that the carrying value of the Americas and Sub-Saharan Africa/Europe reporting units were less than their respective fair values. A goodwill impairment charge of $283.7 million, to write-off the company’s remaining goodwill, was recorded during the quarter ended December 31, 2014.
	During the quarter ended December, 31, 2013 the company performed its annual goodwill impairment assessment and determined that the carrying value of its Asia/Pacific unit exceeded its fair value as a result of the general decline in the level of business and, therefore, expected future cash flow for the company in this region. At the time of the December 2013 goodwill impairment assessment, the Asia/Pacific region continued to be challenged with excess vessel capacity as a result of the significant number of vessels that had been built in this region over the previous 10 years. These additional newbuilds had not been met by a commensurate increase in exploration, development or other activity within the region. In recent years, the company has disposed of older vessels that had worked in the region and transferred vessels out of the region to other regions where market opportunities are currently more robust. In accordance with ASC 350 goodwill is not reallocated based on vessel movements. A goodwill impairment charge of $56.3 million was recorded during the quarter ended December 31, 2013.
	During the first quarter of fiscal 2014, $42.2 million of goodwill related to the acquisition of Troms Offshore was allocated to the Sub-Saharan Africa/Europe segment.
	Goodwill by reportable segment at March 31, 2015 and 2014 is as follows:


	(In thousands)		March 31,		Goodwill acquired			Impairments		March 31,
	(In thousands)		2014		Goodwill acquired			Impairments		2015
	Americas		$	114,237		—			114,237		—
	Sub-Saharan Africa/Europe			169,462		—			169,462		—
	Total carrying amount (A)		$	283,699		—			283,699		—


	(In thousands)		March 31,		Goodwill acquired			Impairments		March 31,
	(In thousands)		2013		Goodwill acquired			Impairments		2014
	Americas		$	114,237		—			—		114,237
	Asia/Pacific			56,283		—			56,283		—
	Sub-Saharan Africa/Europe			127,302		42,160			—		169,462
	Total carrying amount (B)		$	297,822		42,160			—		283,699


	(A)	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
	(B)	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
	Goodwill, as a percentage of total assets and stockholders’ equity, at March 31, is as follows:


			2015		2014
	Goodwill as a percentage of total assets			—		6	%
	Goodwill as a percentage of stockholders’ equity			—		11	%

Restructuring_Charges

Restructuring Charges	12 Months Ended
	Mar. 31, 2015
Restructuring Charges	-17	RESTRUCTURING CHARGE

	In the fourth quarter of fiscal 2015 the Company’s management initiated a plan to begin reorganizing its operations worldwide as a result of the continuing decline in oil prices and the resulting softening demand for the company’s vessels. This plan consists of select employee terminations and early retirements that are intended to eliminate redundant or unneeded positions, reduce costs, and better align our workforce with anticipated activity levels in the geographic areas in which the company presently operates. In connection with these efforts, the company recognized a $4.1 million restructuring charge during the quarter ended March 31, 2015.

	Reorganization efforts to date most significantly included the redeployment of vessels from our Australian operation to other international markets where opportunities to profitably operate such vessels are considered more robust. The departure of these vessels from the Australian market and the associated reductions in onshore and offshore staffing resulted in the termination of a number of mariners who were entitled to severance payments under the terms of the enterprise bargaining agreement and in accordance with Australian labor laws.

Quarterly_Financial_Data

Quarterly Financial Data	12 Months Ended
Quarterly Financial Data	Mar. 31, 2015
Quarterly Financial Data	-18		QUARTERLY FINANCIAL DATA (UNAUDITED)

	Selected financial information for interim periods for the years ended March 31, is as follows:



			Quarter
	(In thousands except per share data)		First		Second		Third			Fourth
	Fiscal 2015
	Revenues		$	385,677		397,524		387,554			324,762
	Operating income(A)			66,004		84,723		(213,580	)		25,672
	Net earnings attributable to Tidewater Inc.			43,673		60,907		(160,694	)		(9,076	)
	Basic earnings per share attributable to Tidewater Inc.		$	0.88		1.23		(3.31	)		(.19	)
	Diluted earnings per share attributable to Tidewater Inc.		$	0.88		1.22		(3.31	)		(.19	)
	Fiscal 2014
	Revenues		$	334,085		367,937		365,248			367,833
	Operating income(A)			43,425		76,565		20,488			61,063
	Net earnings attributable to Tidewater Inc.			30,083		54,172		12,583			43,417
	Basic earnings per share attributable to Tidewater Inc.		$	0.61		1.1		0.25			0.88
	Diluted earnings per share attributable to Tidewater Inc.		$	0.61		1.09		0.25			0.88


	(A)	Operating income consists of revenues less operating costs and expenses, depreciation, vessel operating leases, goodwill impairment, general and administrative expenses and gain on asset dispositions, net, of the company’s operations. Goodwill impairment by quarter for fiscal 2015 and 2014 and gain on asset dispositions, net, by quarter for fiscal 2015 and 2014, are as follows:



	(In thousands)		First		Second		Third			Fourth
	Fiscal 2015:
	Goodwill impairment		$	—		—		(283,699	)		—
	Gain on asset dispositions, net		$	2,943		3,590		(1,537	)		4,275
	Fiscal 2014:
	Goodwill impairment		$	—		—		(56,283	)		—
	Gain on asset dispositions, net		$	2,140		49		7,170			2,363

Subsequent_Events

Subsequent Events	12 Months Ended
	Mar. 31, 2015
Subsequent Events	-19	SUBSEQUENT EVENTS

	In May 2015, the company’s Board of Directors authorized an extension of its current common stock repurchase program from its original expiration date of June 30, 2015 to June 30, 2016. If shares are purchased in open market or privately-negotiated transactions pursuant to this share repurchase program, the company will use its available cash and/or borrowings under its revolving credit facility or other borrowings to fund any share repurchases. As of March 31, 2015, the company had $100 million remaining authorized under this repurchase program available to repurchase shares. The company evaluates share repurchase opportunities relative to other investment opportunities and in the context of current conditions in the credit and capital markets.

	In May 2015, the company amended and extended its existing credit facility. The amended credit agreement matures in June 2019 and provides for a $900 million, five-year credit facility consisting of a (i) $600 million revolving credit facility and a (ii) $300 million term loan facility.



	In May 2015, Troms Offshore entered into a $31.3 million, U.S. dollar denominated, 12 year unsecured borrowing agreement which matures in April 2027 and is secured by a company guarantee. The loan requires semi-annual principal payments of $1.3 million (plus accrued interest) and bears interest at a fixed rate of 2.92% plus a premium based on Tidewater Inc.’s consolidated funded indebtedness to total capitalization ratio (currently equal to 1.30% for a total rate of 4.22%).

	On April 23, 2015, the company notified the international shipyard constructing the six 7,145 BHP towing-supply-class vessels that it was terminating the first three of the six towing-supply vessels as a result of late delivery and requested the return of $36.1 million in aggregate installment payments together with interest on these installments, or all but approximately $1 million of the carrying value of the accumulated costs through March 31, 2015. In May 2015, the company made a demand on the Bank of China refundment guarantees that secure the return of these installments. It is uncertain whether this shipyard or the Bank of China will contest the return of these installments. There was an aggregate $12.7 million in estimated remaining costs to be incurred on these three vessels at the time of the termination.

	After March 31, 2015, the company entered into negotiations with the Chinese shipyard constructing two of the 275-foot deepwater PSVs to resolve issues associated with the delivery of these vessels. In May 2015, the parties settled these issues to their mutual satisfaction. (While the settlement is subject to the issuance by the Bank of China of modified refundment guarantees, the company believes this condition will likely be satisfied.) Under the terms of the settlement, the company can elect to take delivery of one or both completed vessels at any time prior to June 30, 2016. That date is subject to two six month extension periods, each extension requiring the mutual consent of the company and shipyard. If the company does not elect to take delivery of one or both vessels prior to June 30, 2016 (as that date may be extended), (a) the company is entitled to receive the return of $5.4 million in aggregate installment payments per vessel together with interest on these installments (or all but approximately $1 million of the company’s carrying value of the accumulated costs per vessel through March 31, 2015) and (b) the company will be relieved of the obligation to pay to the shipyard the $21.7 million remaining payment per vessel. The shipyard’s obligation to return the $5.4 million (plus interest) per vessel if the company elects not to take delivery of one or both vessels will continue to be secured by Bank of China refundment guarantees.

Valuation_and_Qualifying_Accou

Valuation and Qualifying Accounts

12 Months Ended

Mar. 31, 2015

Valuation and Qualifying Accounts

SCHEDULE II

TIDEWATER INC. AND SUBSIDIARIES

Valuation and Qualifying Accounts

Years Ended March 31, 2015, 2014 and 2013

(In thousands)

Description

Balance at

Additions

Deductions

Balance

Beginning

at Cost

of period

End of

Period

Fiscal 2015

Deducted in balance sheet from Trade accounts receivables:

Allowance for doubtful accounts

35,737

2,405

508

37,634

Fiscal 2014

Deducted in balance sheet from Trade accounts receivables:

Allowance for doubtful accounts

46,332

1,399

11,994

(A)

35,737

Fiscal 2013

Deducted in balance sheet from Trade accounts receivables:

Allowance for doubtful accounts

49,921

900

4,489

(B)

46,332

(A)

Of this amount, $3,151 represents the collections from one customer located in Mexico and $8,843 represents accounts receivable amounts considered uncollectible and removed from accounts receivable with an offsetting reduction to the allowance for doubtful accounts.

(B)

Of this amount, $3,852 is related to the revaluation of the allowance for doubtful accounts related to Venezuelan receivables and $637 related to receivables considered uncollectible and removed from accounts receivable by reducing the allowance for doubtful accounts.

Nature_of_Operations_and_Summa1

Nature of Operations and Summary of Significant Accounting Policies (Policies)

12 Months Ended

Mar. 31, 2015

Nature of Operations

Principles of Consolidation

The consolidated financial statements include the accounts of Tidewater Inc. and its subsidiaries. Intercompany balances and transactions are eliminated in consolidation.

Use of Estimates in Preparation of Financial Statements

Cash Equivalents

The company considers all highly liquid investments with maturities of three months or less when purchased to be cash equivalents.

Marine Operating Supplies

Marine operating supplies, which consist primarily of operating parts and supplies for the company’s vessels, are stated at the lower of weighted-average cost or market.

Properties and Equipment

Depreciation and Amortization

Maintenance and Repairs

Net Properties and Equipment

The following is a summary of net properties and equipment at March 31:

2015

2014

Number

Carrying

Number

Carrying

Of Vessels

Value

Of Vessels

Value

(In thousands)

Owned vessels in active service

242

3,310,476

257

3,281,391

Stacked vessels

38,489

9,743

Marine equipment and other assets under construction

315,552

268,189

Other property and equipment (A)

81,790

62,285

Totals

263

3,746,307

272

3,621,608

(A)

Other property and equipment includes six remotely operated vehicles the company took delivery of in fiscal 2014 and two remotely operated vehicles the company took delivery of in fiscal 2015.

Impairment of Long-Lived Assets

Goodwill

Accrued Property and Liability Losses

(In thousands)

2015

2014

Accrued property and liability losses

14,203

8,917

Pension and Other Postretirement Benefits

Income Taxes

Revenue Recognition

Operating Costs

Foreign Currency Translation

Earnings Per Share

Concentrations of Credit Risk

Stock-Based Compensation

Comprehensive Income

Derivative Instruments and Hedging Activities

Fair Value Measurements

Level 1:

Quoted market prices in active markets for identical assets or liabilities

Level 2:

Observable market based inputs or unobservable inputs that are corroborated by market data

Level 3:

Unobservable inputs that are not corroborated by market data

Reclassifications

Subsequent Events

The company evaluates subsequent events through the time of our filing on the date we issue financial statements.

Accounting Pronouncements

Nature_of_Operations_and_Summa2

Nature of Operations and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Mar. 31, 2015
Summary of Net Properties and Equipment	The following is a summary of net properties and equipment at March 31:


			2015				2014
			Number		Carrying		Number		Carrying
			Of Vessels		Value		Of Vessels		Value
					(In thousands)				(In thousands)

	Owned vessels in active service			242	$	3,310,476		257	$	3,281,391
	Stacked vessels			21		38,489		15		9,743
	Marine equipment and other assets under construction					315,552				268,189
	Other property and equipment (A)					81,790				62,285
	Totals			263	$	3,746,307		272	$	3,621,608


	(A)	Other property and equipment includes six remotely operated vehicles the company took delivery of in fiscal 2014 and two remotely operated vehicles the company took delivery of in fiscal 2015.
Current and Long-Term Liabilities Related to Accrued Property and Liability Losses	The following table discloses the total amount of current and long-term liabilities related to accrued property and liability losses not subject to reinsurance recoverability, but considered currently payable as of March 31:


	(In thousands)		2015		2014
	Accrued property and liability losses		$	14,203		8,917

ACQUISITION_Tables

ACQUISITION (Tables)	12 Months Ended
ACQUISITION (Tables)	Mar. 31, 2015
Allocation of Purchase Price for Acquisition	The following table summarizes the allocation of the purchase price for the acquisition of Troms Offshore:


	(In thousands)
	Cash		$	22,263
	Trade receivables and other current assets			9,816
	Vessels (A)			245,605
	Goodwill (B)			42,160
	Payable and other liabilities			(13,020	)
	Notes payable			(156,824	)
	Total purchase price		$	150,000


	(A)	Includes $10.7 million in costs attributed to vessels under construction.
	(B)	Subsequently written off in December 2014.

Investment_in_Unconsolidated_C1

Investment in Unconsolidated Companies (Tables)	12 Months Ended
Investment in Unconsolidated Companies (Tables)	Mar. 31, 2015
Schedule of Investments in at Equity and Advances to Unconsolidated Companies	Investments in, at equity, and advances to unconsolidated joint venture companies at March 31, were as follows:


	(In thousands)	Percentage			2015	2014
	(In thousands)	Ownership			2015	2014
	Sonatide Marine, Ltd. (Angola)	49	%	$	63,893	62,126
	DTDW Holdings, Ltd. (Nigeria)	40	%		1,951	1,802
	Investments in, at equity, and advances to unconsolidated companies			$	65,844	63,928

INCOME_TAXES_Tables

INCOME TAXES (Tables)	12 Months Ended
INCOME TAXES (Tables)	Mar. 31, 2015
Earnings Before Income Taxes Derived from United States and Non-U.S. Operations	Earnings before income taxes derived from United States and non-U.S. operations for the years ended March 31, are as follows:


	(In thousands)		2015		2014		2013
	Non-U.S.	$	(38,282	)	217,816		246,863
	United States		(27,985	)	(44,768	)	(51,700	)
		$	(66,267	)	173,048		195,163

Income Tax Expense (Benefit)	Income tax expense (benefit) for the years ended March 31, consists of the following:



			U.S.
	(In thousands)		Federal		State		International		Total
	2015
	Current	$	4,869		(9	)	66,452		71,312
	Deferred		(72,389	)	—		—		(72,389	)
		$	(67,520	)	(9	)	66,452		(1,077	)



	2014
	Current	$	(602	)	4		68,100		67,502
	Deferred		(34,226	)	—		(483	)	(34,709	)
		$	(34,828	)	4		67,617		32,793


	2013
	Current	$	(7,633	)	(313	)	64,092		56,146
	Deferred		(11,335	)	—		(398	)	(11,733	)
		$	(18,968	)	(313	)	63,694		44,413

Tax Rate Applicable to Pre-Tax Earnings	The actual income tax expense above differs from the amounts computed by applying the U.S. federal statutory tax rate of 35% to pre-tax earnings as a result of the following for the years ended March 31:



	(In thousands)		2015		2014		2013
	Computed “expected” tax expense	$	(23,193	)	60,567		68,307
	Increase (reduction) resulting from:
	Foreign income taxed at different rates		(13,570	)	(18,536	)	(23,965	)
	Foreign tax credits not previously recognized		—		(483	)	(398	)
	Expenses which are not deductible for tax purposes		472		720		498
	Non-deductible goodwill		15,811		2,941		—
	Reversal of basis difference – sale leaseback		—		(3,369	)	—
	Valuation allowance – deferred tax assets		17,829		(5,821	)	5,821
	Amortization of deferrals associated with intercompany sales to foreign tax jurisdictions		(2,358	)	(1,475	)	(6,232	)
	Expenses which are not deductible for book purposes		(832	)	(2,144	)	—
	Foreign taxes		5,688
	State taxes		(6	)	3		(203	)
	Other, net		(918	)	390		585
		$	(1,077	)	32,793		44,413

Schedule of Effective Tax Rate Applicable to Pre-Tax Earnings	The effective tax rate applicable to pre-tax earnings for the years ended March 31, is as follows:



			2015		2014		2013
	Effective tax rate applicable to pre-tax earnings		1.63	%	18.95	%	22.76	%
Schedule of Significant Portions of Deferred Tax Assets and Deferred Tax Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at March 31, is as follows:



	(In thousands)		2015		2014
	Deferred tax assets:
	Accrued employee benefit plan costs	$	21,874		21,423
	Stock based compensation		8,731		7,162
	Net operating loss and tax credit carryforwards		2,327		2,895
	Other		3,901		2,896
	Gross deferred tax assets		36,833		34,376
	Less valuation allowance		(17,829	)	—
	Net deferred tax assets		19,004		34,376
	Deferred tax liabilities:
	Depreciation and amortization		(19,004	)	(108,929	)
	Gross deferred tax liabilities		(19,004	)	(108,929	)
	Net deferred tax assets (liabilities)	$	—		(74,553	)

Schedule of Deferred Tax Not Recognized	The amount of foreign income that U.S. deferred taxes has not been recognized upon, as of March 31, is as follows:


	(In thousands)		2015
	Foreign income not recognized for U.S. deferred taxes	$	2,578,133
Schedule of Tax Credit Carry-Forwards	The company has the following foreign tax credit carry-forwards that expire in 2022.



	(In thousands)		2015
	Foreign tax credit carry-forwards	$	2,327
Schedule of Uncertain Tax Positions and Income Tax Payable	The company’s balance sheet reflects the following in accordance with ASC 740, Income Taxes at March 31:



	(In thousands)		2015		2014
	Tax liabilities for uncertain tax positions	$	16,305		18,008
	Income tax payable		44,607		36,472
Schedule of Unrecognized Tax Benefits Which Would Lower Effective Tax Rate if Realized	Unrecognized tax benefits, which are not included in the liability for uncertain tax positions above as they have not been recognized in previous tax filings, and which would lower the effective tax rate if realized, at March 31, are as follows:


	(In thousands)		2015
	Unrecognized tax benefit related to state tax issues	$	11,685
	Interest receivable on unrecognized tax benefit related to state tax issues		32
Schedule of Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of all unrecognized tax benefits, including the unrecognized tax benefit related to state tax issues and the liability for uncertain tax positions (but excluding related penalties and interest) for the years ended March 31, are as follows:


	(In thousands)		2015		2014		2013
	Balance at April 1,	$	20,066		14,868		15,727
	Additions based on tax positions related to the current year		1,342		4,393		2,041
	Additions based on tax positions related to prior years		—		2,217		—
	Reductions for tax positions of prior years		—		—		—
	Exchange rate fluctuation		—		—		—
	Settlement and lapse of statute of limitations		(1,710	)	(1,412	)	(2,900	)
	Balance at March 31,	$	19,698		20,066		14,868

Schedule of Tax Benefit From Stock Benefit Transactions	The tax benefit for the years ended March 31, are as follows:


	(In thousands)		2015		2014		2013
	Excess tax benefits on stock benefit transactions	$	(1,784	)	301		359

Indebtedness_Tables

Indebtedness (Tables)	12 Months Ended
Indebtedness (Tables)	Mar. 31, 2015
Summary of Debt Outstanding	The following table summarizes debt outstanding at March 31:


	(In thousands)			2015			2014
	4.61% July 2003 senior notes due fiscal 2016		$	35,000			35,000
	3.28% September 2010 senior notes due fiscal 2016			42,500			42,500
	3.90% September 2010 senior notes due fiscal 2018			44,500			44,500
	3.95% September 2010 senior notes due fiscal 2018			25,000			25,000
	4.12% September 2010 senior notes due fiscal 2019			25,000			25,000
	4.17% September 2010 senior notes due fiscal 2019			25,000			25,000
	4.33% September 2010 senior notes due fiscal 2020			50,000			50,000
	4.51% September 2010 senior notes due fiscal 2021			100,000			100,000
	4.56% September 2010 senior notes due fiscal 2021			65,000			65,000
	4.61% September 2010 senior notes due fiscal 2023			48,000			48,000
	4.06% August 2011 senior notes due fiscal 2019			50,000			50,000
	4.54% August 2011 senior notes due fiscal 2022			65,000			65,000
	4.64% August 2011 senior notes due fiscal 2022			50,000			50,000
	4.26% September 2013 senior notes due fiscal 2021			123,000			123,000
	5.01% September 2013 senior notes due fiscal 2024			250,000			250,000
	5.16% September 2013 senior notes due fiscal 2026			127,000			127,000
	NOK denominated notes due fiscal 2025			20,152			29,837
	NOK denominated notes due fiscal 2026			34,234			50,028
	NOK denominated borrowing agreement due fiscal 2016			2,490			5,837
	NOK denominated borrowing agreement due fiscal 2019			3,112			4,168
	USD denominated notes due fiscal 2027			29,488			—
	Bank term loan due fiscal 2019 (A)			300,000			300,000
	Revolving line of credit due fiscal 2019 (A)			20,000			—
			$	1,534,476			1,514,870
	Less: Current maturities of long-term debt			10,181			9,512
	Total		$	1,524,295			1,505,358


	(A)	In May 2015, the company amended its existing credit facility, extending the due dates of the bank term loan and revolving line of credit until fiscal 2020. Refer to Note (19) for additional information regarding the amended and extended credit facility.
Debt Costs	Interest and debt costs incurred, net of interest capitalized, for the years ended March 31, are as follows:


	(In thousands)		2015			2014			2013
	Interest and debt costs incurred, net of interest capitalized		$	50,029			43,814			29,745
	Interest costs capitalized			13,673			11,497			10,602
	Total interest and debt costs		$	63,702			55,311			40,347

September 2013 Senior Notes
Schedule of Aggregate Amount of Senior Unsecured Notes Outstanding	September 2013 Senior Notes
	On September 30, 2013, the company executed a note purchase agreement for $500 million and issued $300 million of senior unsecured notes to a group of institutional investors. The company issued the remaining $200 million of senior unsecured notes on November 15, 2013. A summary of these outstanding notes at March 31, is as follows:


	(In thousands, except weighted average data)		2015			2014
	Aggregate debt outstanding		$	500,000			500,000
	Weighted average remaining life in years			8.4			9.4
	Weighted average coupon rate on notes outstanding			4.86	%		4.86	%
	Fair value of debt outstanding			516,879			520,979
August 2011 Senior Notes
Schedule of Aggregate Amount of Senior Unsecured Notes Outstanding	August 2011 Senior Notes
	On August 15, 2011, the company issued $165 million of senior unsecured notes to a group of institutional investors. A summary of these outstanding notes at March 31, is as follows:


	(In thousands, except weighted average data)			2015			2014
	Aggregate debt outstanding		$	165,000			165,000
	Weighted average remaining life in years			5.6			6.6
	Weighted average coupon rate on notes outstanding			4.42	%		4.42	%
	Fair value of debt outstanding			167,910			168,653
September 2010 Senior Notes
Schedule of Aggregate Amount of Senior Unsecured Notes Outstanding	September 2010 Senior Notes
	In fiscal 2011, the company completed the sale of $425 million of senior unsecured notes. A summary of the aggregate amount of these outstanding notes at March 31, is as follows:


	(In thousands, except weighted average data)			2015			2014
	Aggregate debt outstanding		$	425,000			425,000
	Weighted average remaining life in years			4.6			5.6
	Weighted average coupon rate on notes outstanding			4.25	%		4.25	%
	Fair value of debt outstanding			431,296			436,254
July 2003 Senior Notes
Schedule of Aggregate Amount of Senior Unsecured Notes Outstanding	July 2003 Senior Notes
	In July 2003, the company completed the sale of $300 million of senior unsecured notes. A summary of the aggregate amount of these outstanding notes at March 31, is as follows:


	(In thousands, except weighted average data)			2015			2014
	Aggregate debt outstanding		$	35,000			35,000
	Weighted average remaining life in years			0.3			1.3
	Weighted average coupon rate on notes outstanding			4.61	%		4.61	%
	Fair value of debt outstanding			35,197			36,018

Employee_Retirement_Plans_Tabl

Employee Retirement Plans (Tables)	12 Months Ended
Employee Retirement Plans (Tables)	Mar. 31, 2015
Schedule of Carrying Value of Trust Assets, Including Unrealized Gains or Losses	The following table summarizes the carrying value of the trust assets, including unrealized gains or losses at March 31:



	(In thousands)		2015			2014
	Investments held in Rabbi Trust		$	9,915			10,285
	Unrealized (loss) gains in carrying value of trust assets			235			92
	Unrealized (loss) gains in carrying value of trust assets are net of income tax expense of			126			49
	Obligations under the supplemental plan			25,510			21,918
Minimum and Maximum Rate of Return Plan Assets	The below table summarizes the supplemental plan’s minimum and maximum rate of return objectives for plan assets:


			Minimum		Maximum
			Expected		Expected
			Rate of Return		Rate of Return
			on Plan Assets		on Plan Assets
	Equity securities		5%		7%
	Debt securities		1%		3%
	Cash and cash equivalents		0%		1%
Schedule of Minimum and Maximum Market Value of Plan Assets	The below table summarizes the supplemental plan’s minimum and maximum market value objectives for plan assets, which are based upon a five to ten year investment horizon:


			Minimum		Maximum
			Market Value		Market Value
			Objective for		Objective for
			Plan Assets		Plan Assets
	Equity securities		55%		75%
	Debt securities		25%		45%
	Percentage of debt securities allowed in below investment grade bonds		0%		20%
	Cash and cash equivalents		0%		10%
Schedule of Asset Allocations	The following table provides the target and actual asset allocations for the pension plan and the supplemental plan:


			Target			Actual as of			Actual as of
			Target			2015			2014
	Pension plan:
	Equity securities			—			—			—
	Debt securities			100	%		95	%		96	%
	Cash and other			—			5	%		4	%
	Total			100	%		100	%		100	%

	Supplemental plan:
	Equity securities			65	%		58	%		60	%
	Debt securities			35	%		39	%		37	%
	Cash and other			—			3	%		3	%
	Total			100	%		100	%		100	%

Fair Value Hierarchy of Plan Assets	The fair value hierarchy for the pension plan and supplemental plan assets measured at fair value as of March 31, 2015, are as follows:


	(In thousands)		Fair Value			Quoted prices in			Significant			Significant
						active			observable			unobservable
						markets			inputs			inputs
						(Level 1)			(Level 2)			(Level 3)
	Pension plan measured at fair value:
	Debt securities:
	Government securities		$	3,116			3,116			—			—
	Collateralized mortgage securities			400			—			400			—
	Corporate debt securities			51,758			—			51,758			—
	Foreign debt securities			1,529			—			1,529			—
	Cash and cash equivalents			1,816			—			1,816			—
	Total		$	58,619			3,116			55,503			—
	Accrued income			866			866			—			—
	Total fair value of plan assets		$	59,485			3,982			55,503			—

	Supplemental plan measured at fair value:
	Equity securities:
	Common stock		$	3,859			3,859			—			—
	Preferred stock			—			—			—			—
	Foreign stock			201			201			—			—
	American depository receipts			1,685			1,685			—			—
	Preferred American depository receipts			15			15			—			—
	Real estate investment trusts			59			59			—			—
	Debt securities:
	Government debt securities			1,926			1,377			549			—
	Open ended mutual funds			1,916			1,916			—			—
	Cash and cash equivalents			377			72			305			—
	Total		$	10,038			9,184			854			—
	Other pending transactions			(123	)		(123	)		—			—
	Total fair value of plan assets		$	9,915			9,061			854			—


	The following table provides the fair value hierarchy for the pension plan and supplemental plan assets measured at fair value as of March 31, 2014:


	(In thousands)		Fair Value			Quoted prices in			Significant			Significant
						active			observable			unobservable
						markets			inputs			inputs
						(Level 1)			(Level 2)			(Level 3)
	Pension plan measured at fair value:
	Debt securities:
	Government securities		$	2,935			2,935			—			—
	Corporate debt securities			50,113			—			50,113			—
	Foreign debt securities			1,443			—			1,443			—
	Cash and cash equivalents			1,511			—			1,511			—
	Total		$	56,002			2,935			53,067			—
	Accrued income			894			894			—			—
	Total fair value of plan assets		$	56,896			3,829			53,067			—

	Supplemental plan measured at fair value:
	Equity securities:
	Common stock		$	4,141			4,141			—			—
	Preferred stock			—			—			—			—
	Foreign stock			231			231			—			—
	American depository receipts			1,809			1,809			—			—
	Preferred American depository receipts			15			15			—			—
	Real estate investment trusts			38			38			—			—
	Debt securities:
	Government debt securities			1,975			1,363			612			—
	Open ended mutual funds			1,797			1,797			—			—
	Cash and cash equivalents			369			57			312			—
Total		$	10,375			9,451			924			—
Other pending transactions			(90	)		(90	)		—			—
Total fair value of plan assets		$	10,285			9,361			924			—

Change in Plan Assets and Obligations	Changes in plan assets and obligations during the years ended March 31, 2015 and 2014 and the funded status of the U.S. defined benefit pension plan and the supplemental plan (referred to collectively as “Pension Benefits”) and the postretirement health care and life insurance plan (referred to as “Other Benefits”) at March 31, are as follows:


			Pension Benefits						Other Benefits
	(In thousands)		2015			2014			2015			2014
	Change in benefit obligation:
	Benefit obligation at beginning of year		$	84,067			88,238			24,114			29,006
	Service cost			825			790			273			405
	Interest cost			3,873			3,581			904			1,048
	Participant contributions			—			—			430			436
	ERRP reimbursement			—			—			—			(26	)
	Plan settlement			—			—			—			—
	Benefits paid			(4,405	)		(4,250	)		(863	)		(962	)
	Actuarial (gain) loss			11,948			(4,292	)		(932	)		(5,793	)
	Benefit obligation at end of year			96,308			84,067			23,926			24,114

	Change in plan assets:
	Fair value of plan assets at beginning of year		$	56,896			59,431			—			—
	Actual return			6,069			776			—			—
	Employer contributions			925			939			433			552
	Participant contributions			—			—			430			436
	ERRP reimbursement			—			—			—			(26	)
	Plan settlement			—			—			—			—
	Benefits paid			(4,405	)		(4,250	)		(863	)		(962	)
	Fair value of plan assets at end of year			59,485			56,896			—			—


	Reconciliation of funded status:
	Fair value of plan assets		$	59,485			56,896			—			—
	Benefit obligation			96,308			84,067			23,926			24,114
	Unfunded status		$	(36,823	)		(27,171	)		(23,926	)		(24,114	)


	Net amount recognized in the balance sheet consists of:
	Current liabilities		$	(1,306	)		(1,162	)		(908	)		(1,129	)
	Noncurrent liabilities			(35,517	)		(26,009	)		(23,018	)		(22,985	)
	Net amount recognized		$	(36,823	)		(27,171	)		(23,926	)		(24,114	)

Schedule of Projected and Accumulated Benefit Obligation	The following table provides the projected benefit obligation and accumulated benefit obligation for the pension plans:


	(In thousands)		2015			2014
	Projected benefit obligation		$	96,308			84,067
	Accumulated benefit obligation			92,808			81,223
Schedule of Accumulated Benefit Obligation in Excess of Plan Assets	The following table provides information for pension plans with an accumulated benefit obligation in excess of plan assets (includes both the pension plan and supplemental plan):


	(In thousands)		2015			2014
	Projected benefit obligation		$	96,308			84,067
	Accumulated benefit obligation			92,808			81,223
	Fair value of plan assets			59,485			56,896
Schedule of Net Periodic Benefit Cost	Net periodic benefit cost for the pension plan and the supplemental plan for the fiscal years ended March 31 include the following components:


	(In thousands)		2015			2014			2013
	Service cost		$	825			790			983
	Interest cost			3,873			3,581			4,098
	Expected return on plan assets			(2,741	)		(2,871	)		(2,748	)
	Amortization of prior service cost			50			50			50
	Recognized actuarial loss			988			1,103			1,648
	Settlement loss			—			—			5,161
	Net periodic pension cost		$	2,995			2,653			9,192

Schedule of Net Periodic Benefit Cost for Postretirement Health Care and Life Insurance Plan	Net periodic benefit cost for the postretirement health care and life insurance plan for the fiscal years ended March 31 include the following components:


	(In thousands)		2015			2014			2013
	Service cost		$	273			405			475
	Interest cost			904			1,048			1,235
	Amortization of prior service cost			(2,032	)		(2,032	)		(2,032	)
	Recognized actuarial loss			(1,299	)		(396	)		—
	Net periodic postretirement benefit		$	(2,154	)		(975	)		(322	)

Schedule of Other Changes in Plan Assets and Benefit Obligations Recognized in OCI	Other changes in plan assets and benefit obligations recognized in other comprehensive income for the fiscal years ended March 31 include the following components:



			Pension Benefits						Other Benefits
	(In thousands)		2015			2014			2015			2014
	Change in benefit obligation
	Net loss (gain)			$ 8,621			(2,196	)		(932	)		(5,793	)
	Settlement loss			—			—			—			—
	Amortization of prior service cost			(50	)		(50	)		2,032			2,032
	Amortization of net (loss) gain			(988	)		(1,103	)		1,299			395
	Other			—			—			—			197
	Total recognized in other comprehensive income (loss)			$ 7,583			(3,349	)		2,399			(3,169	)
	Net of tax			7,583			(2,177	)		1,559			(2,060	)

Schedule of Amounts Recognized in Accumulated Other Comprehensive (Income) Loss	Amounts recognized as a component of accumulated other comprehensive (income) loss as of March 31, 2015 are as follows:


	(In thousands)		Pension Benefits			Other Benefits
	Unrecognized actuarial (gain) loss			$ 21,781			(6,620	)
	Unrecognized prior service cost (benefit)			36			(4,588	)
	Pre-tax amount included in accumulated other comprehensive loss (income)			$ 21,817			(11,208	)

Schedule of Expected Amounts Net Periodic Benefit Costs	The company expects to recognize the following amounts as a component of net periodic benefit costs during the next fiscal year:


	(In thousands)		Pension Benefits			Other Benefits
	Unrecognized actuarial loss			$ (2,213)			582
	Unrecognized prior service cost (benefit)			-36			2,041
Schedule of Assumptions	Assumptions used to determine net benefit obligations for the fiscal years ended March 31, are as follows:


			Pension Benefits						Other Benefits
			2015			2014			2015			2014
	Discount rate			4.00%			4.75%			4.00%			4.75%
	Rates of annual increase in compensation levels			3.00%			3.00%			N/A			N/A
	Assumptions used to determine net periodic benefit costs for the fiscal years ended March 31, are as follows:


			Pension Benefits									Other Benefits
			2015			2014			2013			2015			2014		2013
	Discount rate			4.75%			4.25%			4.75%			4.75%			4.25%		4.75%
	Expected long-term rate of return on assets			5.00%			5.00%			5.00%			N/A			N/A		N/A
	Rates of annual increase in compensation levels			3.00%			3.00%			3.00%			N/A			N/A		N/A
Schedule of Expected Benefit Payments	Based upon the assumptions used to measure the company’s qualified pension and postretirement benefit obligations at March 31, 2015, including pension and postretirement benefits attributable to estimated future employee service, the company expects that benefits to be paid over the next ten years will be as follows:


			(In thousands)
	Year ending March 31,		Pension			Other
	Year ending March 31,		Benefits			Benefits
	2016			$ 5,578			908
	2017			5,818			982
	2018			6,077			1,046
	2019			6,343			1,128
	2020			7,419			1,187
	2021 – 2025			33,918			6,501
	Total 10-year estimated future benefit payments			$ 65,153			11,752

Assumed Health Care Cost Trends Rates	The following table discloses the assumed health care cost trends used in measuring the accumulated postretirement benefit obligation and net periodic postretirement benefit cost at March 31, 2015 for pre-65 medical and prescription drug coverage and for post-65 medical coverage, including expected future trend rates.


			Pre-65			Post-65
	Year ending March 31, 2015
	Accumulated postretirement benefit obligation			7.9	%		6.9	%
	Net periodic postretirement benefit obligation			8.2	%		6.9	%
	Ultimate health care cost trend			4.5	%		4.5	%
	Ultimate year health care cost trend rate is achieved			2029			2029
	Year ending March 31, 2016
	Net periodic postretirement benefit obligation			7.9	%		6.9	%
One-Percentage Rate Change in Assumed Health Care Cost Trend Rates and Its Effects on Accumulated Postretirement Benefit Obligation	A one-percentage rate increase (decrease) in the assumed health care cost trend rates has the following effects on the accumulated postretirement benefit obligation as of March 31:


	(In thousands)		1%			1%
	(In thousands)		Increase			Decrease
	Accumulated postretirement benefit obligation		$	3,702			2,978
	Aggregate service and interest cost			170			138
Number of Shares of Tidewater Common Stock Held	The plan held the following number of shares of Tidewater common stock as of March 31:


			2015			2014
	Number of shares of Tidewater common stock held by 401(k) plan			299,256			273,662
Plan 401 k
Amounts Charged to Expense Related to Contribution Plans	The amounts charged to expense related to the above defined contribution plans, for the fiscal years ended March 31, are as follows:


	(In thousands)		2015			2014			2013
	Defined contribution plans expense, net of forfeitures			$ 4,216			3,854			3,356
	Defined contribution plans forfeitures			52			82			115
Multinational Pension Savings Plan
Amounts Charged to Expense Related to Contribution Plans	The amounts charged to expense related to the multinational pension savings plan contributions, for the fiscal years ended March 31, are as follows:


	(In thousands)		2015			2014			2013
	Multinational pension savings plan expense		$	494			465			420

Other_Assets_Accrued_Expenses_1

Other Assets, Accrued Expenses, Other Current Liabilities, and Other Liabilities and Deferred Credits (Tables)	12 Months Ended
	Mar. 31, 2015
Schedule Of Other Assets	A summary of other assets at March 31, is as follows:



	(In thousands)	2015		2014
	Recoverable insurance losses		$ 10,468		5,219
	Deferred income tax assets		19,004		34,376
	Deferred finance charges – revolver		7,396		8,728
	Savings plans and supplemental plan		23,208		23,212
	Noncurrent tax receivable		—		9,106
	Other		15,120		15,744
			$ 75,196		96,385

Schedule of Accrued Expenses	A summary of accrued expenses at March 31, is as follows:


	(In thousands)	2015		2014
	Payroll and related payables		$ 32,041		27,248
	Commissions payable		8,282		8,263
	Accrued vessel expenses		79,549		96,468
	Accrued interest expense		14,514		14,816
	Other accrued expenses		11,869		10,507
			$ 146,255		157,302

Schedule of Other Current Liabilities	A summary of other current liabilities at March 31, is as follows:



	(In thousands)	2015		2014
	Taxes payable	$	56,620		56,080
	Deferred gain on vessel sales - current		25,057		13,996
	Other		784		491
		$	82,461		70,567

Schedule of Other Liabilities and Deferred Credits	A summary of other liabilities and deferred credits at March 31, is as follows:


	(In thousands)	2015		2014
	Postretirement benefits liability	$	23,018		23,185
	Pension liabilities		41,279		35,234
	Deferred gain on vessel sales		136,238		85,316
	Other		34,573		35,469
		$	235,108		179,204

StockBased_Compensation_and_In1

Stock-Based Compensation and Incentive Plans (Tables)	12 Months Ended
Stock-Based Compensation and Incentive Plans (Tables)	Mar. 31, 2015
Schedule of Common Stock Shares Reserved for Issuance and Shares Available for Grant	The number of common stock shares reserved for issuance under the plans and the number of shares available for future grants at March 31, are as follows:


		March 31,
		2015
	Shares of common stock reserved for issuance under the plans		2,580,880
	Shares of common stock available for future grants		871,674
Fair Value and Assumptions Used for Stock Options Issued	The fair value and assumptions used for the stock options issued during the year ended March 31, 2015, are as follows:


		2015
	Weighted average fair value of stock options granted		$5.54
	Risk-free interest rate		1.82%
	Expected dividend yield		2.40%
	Expected stock price volatility		30%
	Expected stock option life		6.5 years
Schedule of Stock Option Activity	The following table sets forth a summary of stock option activity of the company for fiscal years 2015, 2014 and 2013:


		Weighted-average		Number of
		Exercise Price		Shares
	Outstanding at March 31, 2012		$ 44.93		1,725,424
	Granted		—		—
	Exercised		29.09		(141,542	)
	Expired or cancelled/forfeited		52.47		(27,607	)
	Outstanding at March 31, 2013		46.24		1,556,275
	Granted		—		—
	Exercised		36.86		(186,219	)
	Expired or cancelled/forfeited		—		—
	Outstanding at March 31, 2014		47.51		1,370,056
	Granted		22.80		428,326
	Exercised		35.21		(29,118	)
	Expired or cancelled/forfeited		42.97		(60,058	)
	Outstanding at March 31, 2015		$ 41.69		1,709,206

Options Outstanding, Exercise-Price Ranges	Information regarding the 1,709,206 options outstanding at March 31, 2015 can be grouped into three general exercise-price ranges as follows:


		Exercise Price Range
	At March 31, 2015	$22.80 - $33.83		$45.75 - $48.96			$55.76 - $65.69
	Options outstanding		728,287		394,515			586,404
	Weighted average exercise price of options outstanding		$27.34		$45.86			$56.70
	Weighted average remaining contractual life of options outstanding		7.5 years		5.0 years			2.0 years
	Options exercisable		307,488		394,515			586,404
	Weighted average exercise price of options exercisable		$33.56		$45.86			$56.70
	Weighted average remaining contractual life of options exercisable		4.1 years		5.0 years			2.0 years

Additional Information Regarding Stock Options	Additional information regarding stock options for the years ended March 31, are as follows:


	(In thousands, except number of stock options and weighted average price)	2015		2014			2013
	Intrinsic value of options exercised	$	475		4,059			2,544
	Number of stock options vested		7,527		8,926			144,537
	Fair value of stock options vested	$	40		115			2,154
	Number of options exercisable		1,288,407		1,370,056			1,547,349
	Weighted average exercise price of options exercisable	$	47.86		47.51			46.27
Effect on Basic and Diluted Earnings Per Share, and Stock Option Compensation Expense	Stock option compensation expense along with the reduction effect on basic and diluted earnings per share, and stock option compensation expense for the years ended March 31, are as follows:

	(In thousands, except per share data)	2015		2014			2013
	Stock option compensation expense	$	71		12			2,049
	Basic earnings per share reduced by		0		0			0.03
	Diluted earnings per share reduced by		0		0			0.03

Summary of Restricted Stock Award Activity	The following table sets forth a summary of restricted stock award activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average		Time Based			Performance
		Grant-Date		Shares			Based Shares
		Fair Value
	Non-vested balance at March 31, 2012		51.43		266,418			223,641
	Granted		—		—			—
	Vested		49.53		(110,802	)		—
	Cancelled/forfeited		56.84		(7,067	)		(59,503	)
	Non-vested balance at March 31, 2013		50.95		148,549			164,138
	Granted		55.04		28,963			—
	Vested		56.71		(93,739	)		(1,749	)
	Cancelled/forfeited		35.76		(4,949	)		(56,123	)
	Non-vested balance at March 31, 2014		$ 54.75		78,824			106,266
	Granted		—		—			—
	Vested		57.46		(48,574	)		—
	Cancelled/forfeited		47.09		(5,959	)		(37,861	)
	Non-vested balance at March 31, 2015		$ 56.94		24,291			68,405

Summary of Phantom Stock Activity	The following table sets forth a summary of phantom stock activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average		Time			Performance
		Grant-Date		Based			Based
		Fair Value		Shares			Shares
	Non-vested balance at March 31, 2012		49.23		103,311			28,059
	Granted		50.76		27,100			—
	Vested		43.60		(54,823	)		—
	Cancelled/forfeited		54.26		(6,993	)		(28,059	)
	Non-vested balance at March 31, 2013		51.74		68,595			—
	Granted		48.81		31,736			1,291
	Vested		51.45		(35,095	)		—
	Cancelled/forfeited		50.93		(4,354	)		—
	Non-vested balance at March 31, 2014	$	50.94		60,882			1,291
	Granted		22.80		546,058			—
	Vested		48.47		(33,987	)		—
	Cancelled/forfeited		50.70		(5,482	)
	Non-vested balance at March 31, 2015	$	24.07		567,471			1,291

Summary of Cash-Based Performance Plan Unit Activity	The following table sets forth a summary of cash-based performance plan unit activity of the company for fiscal 2015:


		Weighted-average		Performance
		Grant-Date		Based
		Fair Value		Units
	Non-vested balance at March 31, 2014		—		—
	Granted		1.10		4,519,703
	Vested		—		—
	Cancelled/forfeited		—		—
	Non-vested balance at March 31, 2015	$	1.10		4,519,703

Summary of Deferred Stock Unit Activity	The following table sets forth a summary of deferred stock unit activity of the company for fiscal 2015, 2014 and 2013:


		Weighted-average		Number
		Grant-Date		Of
		Fair Value		Units
	Balance at March 31, 2012		50.56		114,580
	Dividend equivalents reinvested		46.73		2,472
	Retirement distribution		—		—
	Granted		50.48		26,955
	Balance at March 31, 2013		50.48		144,007
	Dividend equivalents reinvested		53.82		2,492
	Retirement distribution		59.65		(26,661	)
	Granted		49.47		26,550
	Balance at March 31, 2014	$	48.68		146,388
	Dividend equivalents reinvested		34.63		3,794
	Retirement distribution		47.50		(21,492	)
	Granted		19.14		56,370
	Balance at March 31, 2015	$	39.53		185,060

Restricted Stock
Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value	Restricted stock award compensation expense and grant date fair value for the years ended March 31, is as follows:


	(In thousands)	2015		2014			2013
	Grant date fair value of restricted stock vested	$	2,791		4,671			5,488
	Restricted stock compensation expense		2,855		4,633			5,987
Restricted Stock Units (RSUs)
Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value	Restricted stock unit compensation expense and grant date fair value for the year ended March 31, is as follows:


	(In thousands)	2015		2014			2013
	Grant date fair value of restricted stock units vested	$	12,080		9,176			4,307
	Restricted stock unit compensation expense		17,214		12,664			7,836
Summary Of Restricted Stock Unit Activity	The following table sets forth a summary of restricted stock unit activity of the company for fiscal 2015, 2014, and 2013:


		Weighted-average		Time			Weight-average			Performance
		Grant-Date		Based			Grant Date			Based Units
		Fair Value		Units			Fair Value
	Non-vested balance at March 31, 2012		$ 54.18		248,288			72.23			84,394
	Granted		50.16		259,158			67.11			84,323
	Vested		54.17		(79,507)			—			—
	Cancelled/forfeited		54.18		(10,274)			72.23			(3,476)
	Non-vested balance at March 31, 2013		$ 51.69		417,665			69.62			165,241
	Granted		49.37		265,937			56.44			91,132
	Vested		52.22		(175,673)			—			—
	Cancelled/forfeited		52.43		(12,720)			—			—
	Non-vested balance at March 31, 2014		$ 50.24		495,209			53.58			256,373
	Granted		54.48		551			—			—
	Vested		50.92		(237,229)			—			—
	Cancelled/forfeited		49.62		(7,381)			—			—
	Non-vested balance at March 31, 2015		$ 49.50		251,150			53.58			256,373

Phantom Stock Plan
Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value	Phantom stock compensation expense and grant date fair value of phantom stock vested for the years ended March 31, are as follows:


	(In thousands)	2015		2014			2013
	Grant date fair value of phantom stock vested	$	1,647		1,806			2,390
	Phantom stock compensation expense		933		1,706			2,507
	Phantom stock compensation costs capitalized as part of an asset		—		—			—
Cash-based Performance Plan
Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value	Cash-based performance unit compensation expense and grant date fair value for the year ended March 31, is as follows:


	(In thousands)	2015
	Grant date fair value of cash-based performance units	$	—
	Cash-based performance unit compensation expense		72
Deferred Stock Unit
Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value	Deferred stock unit compensation expense, which is reflected in general and administrative expenses, for the years ended March 31, are as follows:


	(In thousands)	2015		2014			2013
	Deferred stock units compensation expense (benefit)	$	(2,477)		1,737			1,085

Stockholders_Equity_Tables

Stockholders' Equity (Tables)	12 Months Ended
Stockholders' Equity (Tables)	Mar. 31, 2015
Number of Authorized and Issued Common Stock and Preferred Stock	The number of authorized and issued common stock and preferred stock at March 31, are as follows:


		2015			2014
	Common stock shares authorized		125,000,000			125,000,000
	Common stock par value		$0.10			$0.10
	Common stock shares issued		47,029,359			49,730,442
	Preferred stock shares authorized		3,000,000			3,000,000
	Preferred stock par value		No par			No par
	Preferred stock shares issued		—			—
Schedule of Common Stock Repurchased and Average Price Paid Per Share	The value of common stock repurchased, along with number of shares repurchased, and average price paid per share for the years ended March 31, are as follows:


	(In thousands, except share and per share data)	2015			2014			2013
	Aggregate cost of common stock repurchased	$	99,999			—			85,034
	Shares of common stock repurchased		2,841,976			—			1,856,900
	Average price paid per common share	$	35.19			—			45.79
Schedule of Dividends Declared	The Board of Directors declared the following dividends for the years ended March 31, are as follows:


	(In thousands, except per share data)	2015			2014			2013
	Dividends declared	$	49,127			49,973			49,766
	Dividend per share		1			1			1
Changes in Accumulated Other Comprehensive Income by Component, Net of Tax	The changes in accumulated other comprehensive income by component, net of tax for the years ended March 31, are as follows:




		For the year ended March 31, 2014													For the year ended March 31, 2015
	(in thousands)	Balance			Gains/(losses)			Reclasses		Net		Remaining			Balance			Gains/(losses)			Reclasses		Net			Remaining
		at			recognized			from OCI to		period		balance			at			recognized			from OCI to		period			balance
		3/31/13			in OCI			net income		OCI		3/31/14			3/31/14			in OCI			net income		OCI			3/31/15
	Available for sale securities		(121	)		(92	)		305		213		92			92			(64	)		207		143			235
	Currency translation adjustment		(9,811	)		—			—		—		(9,811	)		(9,811	)		—			—		—			(9,811	)
	Pension/Post-retirement benefits		(4,353	)		4,237			—		4,237		(116	)		(116	)		(9,013	)		—		(9,013	)		(9,129	)
	Interest rate swap		(2,856	)		—			466		466		(2,390	)		(2,390	)		—			717		717			(1,673	)
	Total		(17,141	)		4,145			771		4,916		(12,225	)		(12,225	)		(9,077	)		924		(8,153	)		(20,378	)

Reclassifications from Accumulated Other Comprehensive Loss to Condensed Consolidated Statement of Income	The following table summarizes the reclassifications from accumulated other comprehensive loss to the condensed consolidated statement of income for the years ended March 31,



		Year Ended						Affected line item in the condensed
		March 31,						consolidated statements of income
	(In thousands)	2015			2014
	Realized gains on available for sale securities	$	207			469		Interest income and other, net
	Amortization of interest rate swap		717			717		Interest and other debt costs
	Total pre-tax amounts		924			1,186
	Tax effect		—			415
	Total gains for the period, net of tax	$	924			771

Earnings_per_Share_Tables

Earnings per Share (Tables)	12 Months Ended
Earnings per Share (Tables)	Mar. 31, 2015
Components of Basic and Diluted Earnings Per Share	The components of basic and diluted earnings per share for the years ended March 31, are as follows:



	(In thousands, except share and per share data)	2015			2014		2013

	Net earnings (loss) available to common shareholders (A)	$	(65,190	)		140,255		150,750

	Weighted average outstanding shares of common stock, basic (B)		48,658,840			49,392,749		49,550,391
	Dilutive effect of options and restricted stock awards		—			287,365		183,649
	Weighted average common stock and equivalents (C)		48,658,840			49,680,114		49,734,040

	Earnings per share, basic (A/B)	$	(1.34	)		2.84		3.04
	Earnings per share, diluted (A/C)	$	(1.34	)		2.82		3.03

	Additional information:
	Antidilutive options and restricted stock shares		284,635			34,486		82,758

SaleLeaseback_Arrangements_Tab

Sale/Leaseback Arrangements (Tables)	12 Months Ended
Sale/Leaseback Arrangements (Tables)	Mar. 31, 2015
Details of Number of Vessels, Total Proceeds, Carrying Values at the Time of Sale, Deferred Gains Recognized, Lease Expirations, and Contractual Purchase Option	The following table provides the number of vessels, total proceeds, carrying values at the time of sale, deferred gains recognized, lease expirations, and contractual purchase option timing for the vessels sold and leased back by the company during Fiscal 2015:


	Fiscal 2015 Quarter	Number of		Total				Carrying				Deferred		Lease	Purchase	Purchase
		Vessels		Proceeds				Value at time				Gain at time		Term	Option	Option
								of Sale				of Sale		in Years	Percentage	at end of:
	First	1		$	13,400			$	4,002			$	9,398	7	61%	6^th Year
	Second	1			19,350				8,214				11,136	8.5	47%	8^th Year
	Third	3			78,200				33,233				44,967	8 – 9	60%	7^th or 8^th Year
	Fourth	1			13,000				5,115				7,885	7	50%	6^th Year
		6		$	123,950			$	50,564			$	73,386

	The following table provides the number of vessels, total proceeds, carrying values at the time of sale, deferred gains recognized, lease expirations, and contractual purchase option timing for the vessels sold and leased back by the company during Fiscal 2014:


	Fiscal 2014 Quarter	Number of		Total				Carrying				Deferred		Lease	Purchase	Purchase
		Vessels		Proceeds				Value at time				Gain at time		Term	Option	Option at
								of Sale				of Sale		in Years	Percentage	at end of:
	Second	2		$	65,550			$	34,325			$	31,225	7	55%	6^th Year
	Third	4			141,900				105,649				36,251	7 - 9	54 - 68%	6^th or 8^th Year
	Fourth	4			63,305				32,845				30,460	7 – 10	53 - 59%	6^th or 9^th Year
		10		$	270,755			$	172,819			$	97,936

Schedule of Future Minimum Lease Payments	As of March 31, 2015, the future minimum lease payments for the vessels under the operating lease terms are as follows:


	Fiscal year ending (In thousands)	Fiscal 2015				Fiscal 2014				Total
	Fiscal year ending (In thousands)	Sale/Leaseback				Sale/Leaseback				Total
	2016		$ 9,485				20,879				30,364
	2017		9,485				20,879				30,364
	2018		9,605				23,485				33,090
	2019		10,234				24,800				35,034
	2020		11,497				25,519				37,016
	Thereafter		30,866				39,744				70,610
	Total future lease payments		$ 81,172				155,306				236,478

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
Commitments and Contingencies (Tables)	Mar. 31, 2015
Schedule of Vessel Commitments to Acquire and Construct New Vessels and ROVs, by Vessel Type	The table below summarizes the company’s various vessel commitments to acquire and construct new vessels, by vessel type, as of March 31, 2015:


	(In thousands, except vessel count)		Number of		Total Cost		Invested		Remaining
			Vessels				Through		Balance
							3/31/15		3/31/15
	Vessels under construction:
	Deepwater PSVs (A)			17	$	576,847		223,301		353,546
	Towing supply vessels (A)			6		105,804		79,297		26,507
	Other			1		8,014		8,014		—
	Total vessel commitments			24	$	690,665		310,612		380,053


	(A)	In April 2015, the company cancelled the construction contracts for three towing-supply vessels. There were approximately $13 million of remaining costs to be incurred on these three vessels at the time of termination. In May 2015, the company and the Chinese shipyard that is constructing two 275-foot deepwater PSVs came to an agreement that provides the company an option to take delivery of one or both vessels at any time prior to June 30, 2016 or receive the return of installments aggregating $5.7 million per vessel at the end of this period. There were approximately $41 million of remaining costs to be incurred on these two vessels at the time of the agreement. Refer to Note (19) for a discussion of these vessel construction contract modifications.

Fair_Value_Measurements_and_Di1

Fair Value Measurements and Disclosures (Tables)	12 Months Ended
Fair Value Measurements and Disclosures (Tables)	Mar. 31, 2015
Schedule of Fair Value Other Financial Instruments Measured	The following table provides the fair value hierarchy for the company’s other financial instruments measured as of March 31, 2015:


	(In thousands)	Total		Quoted prices in		Significant		Significant
				active markets		observable		unobservable
				(Level 1)		inputs		inputs
						(Level 2)		(Level 3)
	Money market cash equivalents	$	3,007		3,007		—		—
	Total fair value of assets	$	3,007		3,007		—		—


	The following table provides the fair value hierarchy for the company’s other financial instruments measured as of March 31, 2014:


	(In thousands)	Total		Quoted prices in		Significant		Significant
				active markets		observable		unobservable
				(Level 1)		inputs		inputs
						(Level 2)		(Level 3)
	Money market cash equivalents	$	16,559		16,559		—		—
	Total fair value of assets	$	16,559		16,559		—		—

Summary of Gain on Assets Disposition	The below table summarizes the combined fair value of the assets that incurred impairments along with the amount of impairment during the years ended March 31. The fair values of impaired assets are based on expected net proceeds from asset sales or appraisals performed by third parties. The impairment charges were recorded in gain on asset dispositions, net.


	(In thousands)	2015		2014		2013
	Amount of impairment incurred	$	14,525		9,341		8,078
	Combined fair value of assets incurring impairment		28,509		11,149		14,733

Gain_on_Disposition_of_Assets_1

Gain on Disposition of Assets, Net (Tables)	12 Months Ended
Gain on Disposition of Assets, Net (Tables)	Mar. 31, 2015
Schedule of Gain on Disposition of Assets	The number of vessels disposed along with the gain on the dispositions for the years ended March 31, are as follows:


	(In thousands, except number of vessels disposed)	2015		2014		2013
	Gain on vessels disposed	$	2,988		12,247		12,191
	Number of vessels disposed		13		48		32

Segment_Information_Geographic1

Segment Information, Geographical Data and Major Customers (Tables)	12 Months Ended
	Mar. 31, 2015
Segment Information, Geographical Data and Major Customers	The following table provides a comparison of revenues, vessel operating profit, depreciation and amortization, and additions to properties and equipment for the years ended March 31. Vessel revenues and operating costs relate to vessels owned and operated by the company while other operating revenues relate to the activities of the company’s shipyards, brokered vessels and other miscellaneous marine-related businesses.



	(In thousands)		2015			2014			2013
	Revenues:
	Vessel revenues:
	Americas		$	505,699			410,731			327,059
	Asia/Pacific			150,820			154,618			184,014
	Middle East/North Africa			205,787			186,524			149,412
	Sub-Saharan Africa/Europe			606,052			666,588			569,513
				1,468,358			1,418,461			1,229,998
	Other operating revenues			27,159			16,642			14,167
			$	1,495,517			1,435,103			1,244,165

	Vessel operating profit:
	Americas		$	122,988			90,936			40,318
	Asia/Pacific			11,541			29,044			43,704
	Middle East/North Africa			37,258			42,736			39,069
	Sub-Saharan Africa/Europe			122,169			136,092			129,460
				293,956			298,808			252,551
	Other operating loss			(8,022	)		(1,930	)		(833	)
				285,934			296,878			251,718

	Corporate general and administrative expenses (A)			(40,621	)		(47,703	)		(48,704	)
	Corporate depreciation			(4,014	)		(3,073	)		(3,391	)
	Corporate expenses			(44,635	)		(50,776	)		(52,095	)

	Gain on asset dispositions, net			9,271			11,722			6,609
	Goodwill impairment			(283,699	)		(56,283	)		—
	Restructuring charge			(4,052	)		—			—
	Operating income (loss)			(37,181	)		201,541			206,232
	Foreign exchange gain			8,678			1,541			3,011
	Equity in net earnings of unconsolidated companies			10,179			15,801			12,189
	Interest income and other, net			1,927			2,123			3,476
	Loss on early extinguishment of debt			—			(4,144	)		—
	Interest and other debt costs			(50,029	)		(43,814	)		(29,745	)
	Earnings (loss) before income taxes		$	(66,426	)		173,048			195,163

	Depreciation and amortization:
	Americas		$	47,682			43,298			40,454
	Asia/Pacific			18,383			17,174			19,416
	Middle East/North Africa			27,538			24,441			18,784
	Sub-Saharan Africa/Europe			73,614			79,199			65,241
				167,217			164,112			143,895
	Other			3,973			295			13
	Corporate			4,014			3,073			3,391
			$	175,204			167,480			147,299

	Additions to properties and equipment:
	Americas		$	94,137			99,798			52,299
	Asia/Pacific			91,497			2,586			19,858
	Middle East/North Africa			1,842			8,042			3,833
	Sub-Saharan Africa/Europe (B)			36,105			488,984			197,534
				223,581			599,410			273,524
	Other			18,571			31,841			—
	Corporate (C)			124,411			175,233			179,058
			$	366,563			806,484			452,582

	Total assets (D):
	Americas		$	1,016,133			1,017,736			880,368
	Asia/Pacific			506,265			421,379			607,546
	Middle East/North Africa			666,983			613,303			507,124
	Sub-Saharan Africa/Europe			2,064,010			2,383,507			1,706,355
			4,253,391			4,435,925			3,701,393
Other			49,554			31,545			5,102
			4,302,945			4,467,470			3,706,495
Investments in and advances to unconsolidated companies			65,844			63,928			46,047
			4,368,789			4,531,398			3,752,542
Corporate (E)			387,373			354,431			415,513
		$	4,756,162			4,885,829			4,168,055



(A)	Included in Corporate general and administrative expenses for the year ended March 31, 2014 and 2013 are transaction costs of $3.7 million related to the acquisition of Troms Offshore and a settlement charge of $5.2 million related to the payment of retirement benefits to a former Chief Executive Officer, respectively.


(B)	Included in Sub-Saharan Africa/Europe for the year ended March 31, 2014 is $245.6 million related to vessels acquired through the acquisition of Troms Offshore.


(C)	Included in Corporate are additions to properties and equipment relating to vessels currently under construction which have not yet been assigned to a non-corporate reporting segment as of the dates presented.


(D)	Marine support services are conducted worldwide with assets that are highly mobile. Revenues are principally derived from offshore service vessels, which regularly and routinely move from one operating area to another, often to and from offshore operating areas in different continents. Because of this asset mobility, revenues and long-lived assets attributable to the company’s international marine operations in any one country are not material.


(E)	Included in Corporate are vessels currently under construction which have not yet been assigned to a non-corporate reporting segment. The vessel construction costs will be reported in Corporate until the earlier of the vessels being assigned to a non-corporate reporting segment or the vessels’ delivery. At March 31, 2015, 2014 and 2013, $235.2 million, $228.9 million and $229.3 million, respectively, of vessel construction costs are included in Corporate.
Schedule of Segment Reporting Information, Revenue by Vessel Class	The following table discloses the amount of revenue by segment, and in total for the worldwide fleet, along with the respective percentage of total vessel revenue for the years ended March 31,:


	Revenue by vessel class:		2015			% of Vessel			2014			% of Vessel			2013		% of Vessel
	(In thousands):		2015			Revenue			2014			Revenue			2013		Revenue
	Americas fleet:
	Deepwater		$	353,232			24	%		263,750			18	%		179,032		15	%
	Towing-supply			125,029			9	%		115,055			8	%		120,817		10	%
	Other			27,438			2	%		31,926			3	%		27,210		2	%
	Total		$	505,699			35	%		410,731			29	%		327,059		27	%
	Asia/Pacific fleet:
	Deepwater		$	94,538			6	%		88,191			6	%		96,118		8	%
	Towing-supply			53,281			4	%		62,630			5	%		84,217		7	%
	Other			3,001			<1	%		3,797			<1	%		3,679		<1	%
	Total		$	150,820			10	%		154,618			11	%		184,014		15	%
	Middle East/North Africa fleet:
	Deepwater		$	85,279			6	%		66,503			5	%		55,945		5	%
	Towing-supply			117,232			8	%		116,720			8	%		89,902		7	%
	Other			3,276			<1	%		3,301			<1	%		3,565		<1	%
	Total		$	205,787			14	%		186,524			13	%		149,412		12	%
	Sub-Saharan Africa/Europe fleet:
	Deepwater		$	326,315			22	%		364,722			26	%		273,544		22	%
	Towing-supply			208,324			14	%		231,224			16	%		226,357		18	%
	Other			71,413			5	%		70,642			5	%		69,612		6	%
	Total		$	606,052			41	%		666,588			47	%		569,513		46	%
	Worldwide fleet:
	Deepwater		$	859,364			58	%		783,166			55	%		604,639		50	%
	Towing-supply			503,866			35	%		525,629			37	%		521,293		42	%
	Other			105,128			7	%		109,666			8	%		104,066		8	%
	Total		$	1,468,358			100	%		1,418,461			100	%		1,229,998		100	%

Customers Accounted for 10% or more of Total Revenues	The following table discloses our customers that accounted for 10% or more of total revenues during the years ended March 31:


			2015			2014			2013
	Chevron Corporation			12.7	%		18.1	%		17.8	%
	Petroleo Brasileiro SA			11.8	%		8.6	%		8.6	%
	BP plc			10.1	%		8.9	%		7.9	%

Goodwill_Tables

Goodwill (Tables)	12 Months Ended
Goodwill (Tables)	Mar. 31, 2015
Schedule of Goodwill by Reportable Segment	Goodwill by reportable segment at March 31, 2015 and 2014 is as follows:


	(In thousands)		March 31,		Goodwill acquired			Impairments		March 31,
	(In thousands)		2014		Goodwill acquired			Impairments		2015
	Americas		$	114,237		—			114,237		—
	Sub-Saharan Africa/Europe			169,462		—			169,462		—
	Total carrying amount (A)		$	283,699		—			283,699		—


	(In thousands)		March 31,		Goodwill acquired			Impairments		March 31,
	(In thousands)		2013		Goodwill acquired			Impairments		2014
	Americas		$	114,237		—			—		114,237
	Asia/Pacific			56,283		—			56,283		—
	Sub-Saharan Africa/Europe			127,302		42,160			—		169,462
	Total carrying amount (B)		$	297,822		42,160			—		283,699


	(A)	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
	(B)	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
Goodwill
Schedule of Goodwill as Percentage of Assets and Stockholders' Equity	Goodwill, as a percentage of total assets and stockholders’ equity, at March 31, is as follows:


			2015		2014
	Goodwill as a percentage of total assets			—		6	%
	Goodwill as a percentage of stockholders’ equity			—		11	%

Quarterly_Financial_Data_Table

Quarterly Financial Data (Tables)	12 Months Ended
Quarterly Financial Data (Tables)	Mar. 31, 2015
Schedule of Quarterly Financial Information	Selected financial information for interim periods for the years ended March 31, is as follows:



			Quarter
	(In thousands except per share data)		First		Second		Third			Fourth
	Fiscal 2015
	Revenues		$	385,677		397,524		387,554			324,762
	Operating income(A)			66,004		84,723		(213,580	)		25,672
	Net earnings attributable to Tidewater Inc.			43,673		60,907		(160,694	)		(9,076	)
	Basic earnings per share attributable to Tidewater Inc.		$	0.88		1.23		(3.31	)		(.19	)
	Diluted earnings per share attributable to Tidewater Inc.		$	0.88		1.22		(3.31	)		(.19	)
	Fiscal 2014
	Revenues		$	334,085		367,937		365,248			367,833
	Operating income(A)			43,425		76,565		20,488			61,063
	Net earnings attributable to Tidewater Inc.			30,083		54,172		12,583			43,417
	Basic earnings per share attributable to Tidewater Inc.		$	0.61		1.1		0.25			0.88
	Diluted earnings per share attributable to Tidewater Inc.		$	0.61		1.09		0.25			0.88


	(A)	Operating income consists of revenues less operating costs and expenses, depreciation, vessel operating leases, goodwill impairment, general and administrative expenses and gain on asset dispositions, net, of the company’s operations. Goodwill impairment by quarter for fiscal 2015 and 2014 and gain on asset dispositions, net, by quarter for fiscal 2015 and 2014, are as follows:



	(In thousands)		First		Second		Third			Fourth
	Fiscal 2015:
	Goodwill impairment		$	—		—		(283,699	)		—
	Gain on asset dispositions, net		$	2,943		3,590		(1,537	)		4,275
	Fiscal 2014:
	Goodwill impairment		$	—		—		(56,283	)		—
	Gain on asset dispositions, net		$	2,140		49		7,170			2,363

Nature_of_Operations_and_Summa3

Nature of Operations and Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013	Jun. 04, 2013
	Dec. 31, 2014	Dec. 31, 2013	M		Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013	Jun. 04, 2013
Property, Plant and Equipment [Line Items]
Extended useful life, months			30
Inspection interval			The majority of the company's vessels require certification inspections twice in every five year period
Goodwill					$283,699	[1],[2]	$297,822	[1]
Goodwill impairment	283,699	56,283	283,699	[2]	56,283
Troms Offshore Supply AS
Property, Plant and Equipment [Line Items]
Goodwill									$42,200	$42,160	[3]
Maximum
Property, Plant and Equipment [Line Items]
Highly liquid investments, maturities			3 months
Marine Equipment \| Maximum
Property, Plant and Equipment [Line Items]
Percentage of salvage values			10.00%
Marine Equipment \| Maximum \| From Date of Construction
Property, Plant and Equipment [Line Items]
Estimated useful lives, years			25 years
Marine Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Percentage of salvage values			5.00%
Marine Equipment \| Minimum \| From Date of Construction
Property, Plant and Equipment [Line Items]
Estimated useful lives, years			15 years
Marine Equipment \| Minimum \| Regardless of Date Constructed
Property, Plant and Equipment [Line Items]
Estimated useful lives, years			6 years
Other Property Plant and Equipment \| Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives, years			30 years
Other Property Plant and Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives, years			3 years
Stacked Vessels
Property, Plant and Equipment [Line Items]
Property plant and equipment average age			20.7		32.2

[1]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
[2]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
[3]	Subsequently written off in December 2014.

Summary_of_Net_Properties_and_

Summary of Net Properties and Equipment (Detail) (USD $)	Mar. 31, 2015		Mar. 31, 2014
In Thousands, unless otherwise specified	Vessel		Vessel
Property, Plant and Equipment [Line Items]
Number Of Vessels	263		272
Carrying Value	$3,746,307		$3,621,608
Owned Vessels in Active Service
Property, Plant and Equipment [Line Items]
Number Of Vessels	242		257
Carrying Value	3,310,476		3,281,391
Stacked Vessels
Property, Plant and Equipment [Line Items]
Number Of Vessels	21		15
Carrying Value	38,489		9,743
Marine Equipment and Other Assets Under Construction
Property, Plant and Equipment [Line Items]
Carrying Value	315,552		268,189
Other Property Plant and Equipment
Property, Plant and Equipment [Line Items]
Carrying Value	$81,790	[1]	$62,285	[1]

[1]	Other property and equipment includes six remotely operated vehicles the company took delivery of in fiscal 2014 and two remotely operated vehicles the company took delivery of in fiscal 2015.

Summary_of_Net_Properties_and_1

Summary of Net Properties and Equipment (Parenthetical) (Detail) (Other Property Plant and Equipment)	Mar. 31, 2015	Mar. 31, 2014
	Vehicle	Vehicle
Other Property Plant and Equipment
Property, Plant and Equipment [Line Items]
Number of remotely operated vehicles	2	6

Schedule_of_Accrued_Property_a

Schedule of Accrued Property and Liability Losses (Detail) (Accrued property and liability losses, USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accrued property and liability losses
Schedule of Accrued Liabilities [Line Items]
Accrued property and liability losses	$14,203	$8,917

Acquisition_Additional_Informa

Acquisition - Additional Information (Detail) (USD $)	0 Months Ended
Acquisition - Additional Information (Detail) (USD $)	Jun. 04, 2013		Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013
Business Acquisition [Line Items]
Business acquisition, Goodwill			$283,699,000	[1],[2]	$297,822,000	[1]
Troms Offshore Supply AS
Business Acquisition [Line Items]
Business acquisition, description of acquired entity	Troms Offshore owned four deepwater PSVs, and had two additional deepwater PSVs under construction, one delivered shortly after the acquisition and the other delivered in January 2014.
Business acquisition, cash paid	150,000,000
Business acquisition, debt assumed	261,300,000
Business acquisition, Goodwill	$42,160,000	[3]					$42,200,000

[1]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
[2]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
[3]	Subsequently written off in December 2014.

Allocation_of_Purchase_Price_f

Allocation of Purchase Price for Acquisition (Detail) (USD $)	Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013	Jun. 04, 2013
In Thousands, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013		Jun. 30, 2013	Jun. 04, 2013
Business Combination Allocation of Purchase Price [Line Items]
Goodwill	$283,699	[1],[2]	$297,822	[1]
Troms Offshore Supply AS
Business Combination Allocation of Purchase Price [Line Items]
Cash						22,263
Trade receivables and other current assets						9,816
Vessels						245,605	[3]
Goodwill					42,200	42,160	[4]
Payable and other liabilities						-13,020
Notes payable						-156,824
Total purchase price						$150,000

[1]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
[2]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
[3]	Includes $10.7 million in costs attributed to vessels under construction.
[4]	Subsequently written off in December 2014.

Acquisition_Additional_Informa1

Acquisition - Additional Information (Parenthetical) (Detail) (Vessels, Troms Offshore Supply AS, USD $)	0 Months Ended
In Millions, unless otherwise specified	Jun. 04, 2013
Vessels \| Troms Offshore Supply AS
Business Acquisition [Line Items]
Costs attributed to vessels under construction	$10.70

Investment_in_Unconsolidated_C2

Investment in Unconsolidated Companies - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2015
DTDW Holdings, Ltd.
Schedule of Equity Method Investments [Line Items]
Ownership percentage in unconsolidated affiliates	40.00%	40.00%
Advances to unconsolidated companies	$1.90
Amount of vessel sold	23.3
Gain realized from vessel sold	7.9
Deferred gain recognized from vessel sold	$5.20
Maximum
Schedule of Equity Method Investments [Line Items]
Ownership percentage in unconsolidated affiliates		50.00%

Investment_in_Unconsolidated_C3

Investment in Unconsolidated Companies (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Investments in, at equity, and advances to unconsolidated companies	$65,844	$63,928
Sonatide Marine, Ltd.
Schedule of Equity Method Investments [Line Items]
Ownership percentage in unconsolidated affiliates	49.00%
Investments in, at equity, and advances to unconsolidated companies	63,893	62,126
DTDW Holdings, Ltd.
Schedule of Equity Method Investments [Line Items]
Ownership percentage in unconsolidated affiliates	40.00%		40.00%
Investments in, at equity, and advances to unconsolidated companies	$1,951	$1,802

Schedule_of_Earning_Before_Inc

Schedule of Earning Before Income Taxes Derived from United States and Non-U.S Operation (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]
Earnings before income taxes, Non-U.S	($38,282)	$217,816	$246,863
Earnings before income taxes, United States	-27,985	-44,768	-51,700
Total pre-tax amounts	($66,267)	$173,048	$195,163

Schedule_of_Income_Tax_Expense

Schedule of Income Tax Expense (Benefit) (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Reconciliation of Provision of Income Taxes [Line Items]
Current, Federal, Income tax expense (benefit)	$4,869	($602)	($7,633)
Deferred, Federal, Income tax expense (benefit)	-72,389	-34,226	-11,335
Federal, Income tax expense (benefit)	-67,520	-34,828	-18,968
Current, State, Income tax expense (benefit)	-9	4	-313
Deferred, State, Income tax expense (benefit)	0	0	0
State, Income tax expense (benefit)	-9	4	-313
Current, International, Income tax expense (benefit)	66,452	68,100	64,092
Deferred, International, Income tax expense (benefit)		-483	-398
International, Income tax expense (benefit)	66,452	67,617	63,694
Current, Total, Income tax expense (benefit)	71,312	67,502	56,146
Deferred, Total, Income tax expense (benefit)	-72,389	-34,709	-11,733
Income tax expense (benefit), Total	($1,077)	$32,793	$44,413

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Income Tax [Line Items]
Federal statutory tax rate	35.00%
Valuation allowance	$17,829
Foreign tax credit carry-forwards expiry period	2022
Income tax penalties and interest	$8,300

Schedule_of_Tax_Rate_Applicabl

Schedule of Tax Rate Applicable to Pre-Tax Earning, U.S. Federal Statutory Rate (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Reconciliation of Statutory Federal Tax Rate [Line Items]
Computed "expected" tax expense	($23,193)	$60,567	$68,307
Foreign income taxed at different rates	-13,570	-18,536	-23,965
Foreign tax credits not previously recognized		-483	-398
Expenses which are not deductible for tax purposes	472	720	498
Non-deductible goodwill	15,811	2,941
Reversal of basis difference - sale leaseback		-3,369
Valuation allowance - deferred tax assets	17,829	-5,821	5,821
Amortization of deferrals associated with intercompany sales to foreign tax jurisdictions	-2,358	-1,475	-6,232
Expenses which are not deductible for book purposes	-832	-2,144
Foreign taxes	5,688
State taxes	-6	3	-203
Other, net	-918	390	585
Income tax expense (benefit), Total	($1,077)	$32,793	$44,413

Schedule_of_Effective_Tax_Rate

Schedule of Effective Tax Rate Applicable to Pre-Tax Earnings (Detail)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Schedule of Effective Tax Rate Reconciliation [Line Items]
Effective tax rate applicable to pre-tax earnings	1.63%	18.95%	22.76%

Schedule_of_Deferred_Tax_Asset

Schedule of Deferred Tax Assets and Deferred Tax Liabilities (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Accrued employee benefit plan costs	$21,874	$21,423
Stock based compensation	8,731	7,162
Net operating loss and tax credit carryforwards	2,327	2,895
Other	3,901	2,896
Gross deferred tax assets	36,833	34,376
Less valuation allowance	-17,829
Net deferred tax assets	19,004	34,376
Depreciation and amortization	-19,004	-108,929
Gross deferred tax liabilities	-19,004	-108,929
Net deferred tax assets (liabilities)		($74,553)

Schedule_of_Deferred_Tax_Not_R

Schedule of Deferred Tax Not Recognized (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Deferred Tax Assets Liabilities [Line Items]
Foreign income not recognized for U.S. deferred taxes	$2,578,133

Schedule_of_Tax_Credit_CarryFo

Schedule of Tax Credit Carry-Forwards (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Tax Credit Carryforward [Line Items]
Foreign tax credit carry-forwards	$2,327

Schedule_of_Uncertain_Tax_Posi

Schedule of Uncertain Tax Positions and Income Tax Payable (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Tax [Line Items]
Tax liabilities for uncertain tax positions	$16,305	$18,008
Income tax payable	$44,607	$36,472

Schedule_of_Unrecognized_Tax_B

Schedule of Unrecognized Tax Benefits Which Would Lower Effective Tax Rate if Realized (Detail) (State and Local Jurisdiction, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
State and Local Jurisdiction
Income Tax Contingency [Line Items]
Unrecognized tax benefit related to state tax issues	$11,685
Interest receivable on unrecognized tax benefit related to state tax issues	$32

Schedule_of_Reconciliation_of_

Schedule of Reconciliation of Unrecognized Tax Benefits (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Schedule of Unrecognized Tax Benefits [Line Items]
Balance at April 1,	$20,066	$14,868	$15,727
Additions based on tax positions related to the current year	1,342	4,393	2,041
Additions based on tax positions related to prior years		2,217
Reductions for tax positions of prior years	0	0	0
Exchange rate fluctuation	0	0	0
Settlement and lapse of statute of limitations	-1,710	-1,412	-2,900
Balance at March 31,	$19,698	$20,066	$14,868

Schedule_of_Tax_Benefit_from_S

Schedule of Tax Benefit from Stock Benefit Transactions (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Income Taxes [Line Items]
Excess tax benefits on stock benefit transactions	($1,784)	$301	$359

Indebtedness_Revolving_Credit_

Indebtedness - Revolving Credit and Term Loan Agreement - Additional Information (Detail) (USD $)	12 Months Ended
	Mar. 31, 2015
Minimum
Debt [Line Items]
Interest coverage ratio	300.00%
Commitment fees on the unused portion of credit facility	0.15%
Maximum
Debt [Line Items]
Consolidated debt to consolidated total capitalization, ratio	55.00%
Commitment fees on the unused portion of credit facility	0.30%
Eurodollar Rates \| Minimum
Debt [Line Items]
Revolving credit rate	1.25%
Eurodollar Rates \| Maximum
Debt [Line Items]
Revolving credit rate	2.00%
Current Credit Facility
Debt [Line Items]
Credit facility expiration date	2018-06
Revolving credit facility	900,000,000
Credit facility term	5 years
Revolving line of credit	600,000,000
Term loan	300,000,000
Revolving credit facility, remaining borrowing capacity	580,000,000
Prime or Federal Funds \| Minimum
Debt [Line Items]
Revolving credit rate	0.25%
Prime or Federal Funds \| Maximum
Debt [Line Items]
Revolving credit rate	1.00%
Term Loan Facility
Debt [Line Items]
Outstanding borrowing	300,000,000
Revolving Credit Agreement
Debt [Line Items]
Outstanding borrowing	20,000,000

Indebtedness_Senior_Debt_Notes

Indebtedness - Senior Debt Notes - Additional Information (Detail)

12 Months Ended

3 Months Ended

1 Months Ended

3 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

0 Months Ended

12 Months Ended

Mar. 31, 2014

Mar. 31, 2015

Jun. 30, 2013

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2015

31-May-14

31-May-12

Jun. 30, 2013

Mar. 31, 2015

Jan. 31, 2014

Mar. 31, 2015

Jan. 31, 2014

31-May-12

Mar. 31, 2015

Sep. 30, 2013

Mar. 31, 2015

31-May-12

Jun. 30, 2013

Jan. 31, 2014

Mar. 31, 2015

31-May-12

Jun. 30, 2013

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2011

Mar. 31, 2015

Jul. 31, 2003

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2015

Nov. 15, 2013

Sep. 30, 2013

Mar. 31, 2015

Mar. 31, 2014

Sep. 30, 2013

Mar. 31, 2015

Aug. 15, 2011

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2015

USD ($)

Troms Offshore Supply AS

Notes Due May 2015

Senior Notes Due 2019

Notes Due April 2027

Notes Due January 2026

Notes Due May 2024

Public bonds

Minimum

Maximum

September 2010 Senior Unsecured Notes

July 2003 Senior Unsecured Notes

September 2013 Senior Unsecured Notes

August 2011 Senior Unsecured Notes

USD ($)

NOK

USD ($)

NOK

Floating rate debt

Fixed rate debt

Troms Offshore Supply AS

Notes Due May 2015

Senior Notes Due 2019

Notes Due January 2026

Notes Due May 2015

Senior Notes Due 2019

USD ($)

Not classified as current maturities of long-term debt

Minimum

Maximum

USD ($)

Not classified as current maturities of long-term debt

Minimum

Maximum

USD ($)

Minimum

Maximum

USD ($)

Minimum

Maximum

USD ($)

NOK

USD ($)

NOK

U.S. dollar denominated debt

USD ($)

NOK

USD ($)

NOK

USD ($)

NOK

USD ($)

NOK

USD ($)

NOK

Troms Offshore Supply AS

USD ($)

Debt [Line Items]

Senior note issuable amount under purchase agreement

$500,000,000

Sale of debt outstanding

425,000,000

300,000,000

200,000,000

300,000,000

500,000,000

165,000,000

Debt instrument maturity, in years

5 years

12 years

7 years

12 years

7 years

12 years

8 years

10 years

Consolidated debt to consolidated total capitalization, ratio

55.00%

Interest coverage ratio

300.00%

After-tax loss relating to interest rate hedges

1,800,000

2,400,000

Pre-tax loss relating to interest rate hedges

2,600,000

3,700,000

Aggregate debt outstanding

425,000,000

42,500,000

35,000,000

500,000,000

165,000,000

Debt instrument maturity, month and year

2015-05

2019-06

2027-01

2026-01

2024-05

2015-12

2015-07

Debt instruments face amount

35,000,000

25,000,000

29,500,000

300,000,000

204,400,000

Semi-annual principal payments

1,200,000

12,500,000

8,500,000

Debt instrument bearing floating interest rate

2.91%

2.31%

Indebtedness rate

1.30%

1.50%

Total capitalization rate

4.21%

3.81%

5.38%

Debt instrument outstanding amount

1,514,870,000

1,534,476,000

5,600,000

45,000,000

5,600,000

45,000,000

54,400,000

436,900,000

29,500,000

34,200,000

275,000,000

20,200,000

161,900,000

Debt instrument bearing interest rate

3.88%

6.38%

Interest rate

2.00%

3.50%

Debt instrument repayment

15,000,000

Debt instrument estimated fair value

54,100,000

435,000,000

29,500,000

Debt extinguished amount

32,500,000

188,900,000

82,100,000

500,000,000

Repayment of bond at average price as a percentage of par value

105.00%

Loss on early extinguishment of bond

($4,144,000)

($4,100,000)

-26,000,000

Schedule_of_Aggregate_Amount_o

Schedule of Aggregate Amount of Senior Unsecured Notes Outstanding (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
September 2013 Senior Unsecured Notes
Debt [Line Items]
Aggregate debt outstanding	$500,000	$500,000
Weighted average remaining life in years	8 years 4 months 24 days	9 years 4 months 24 days
Weighted average coupon rate on notes outstanding	4.86%	4.86%
Fair value of debt outstanding	516,879	520,979
August 2011 Senior Unsecured Notes
Debt [Line Items]
Aggregate debt outstanding	165,000	165,000
Weighted average remaining life in years	5 years 7 months 6 days	6 years 7 months 6 days
Weighted average coupon rate on notes outstanding	4.42%	4.42%
Fair value of debt outstanding	167,910	168,653
September 2010 Senior Unsecured Notes
Debt [Line Items]
Aggregate debt outstanding	425,000	425,000
Weighted average remaining life in years	4 years 7 months 6 days	5 years 7 months 6 days
Weighted average coupon rate on notes outstanding	4.25%	4.25%
Fair value of debt outstanding	431,296	436,254
July 2003 Senior Unsecured Notes
Debt [Line Items]
Aggregate debt outstanding	35,000	35,000
Weighted average remaining life in years	3 months 18 days	1 year 3 months 18 days
Weighted average coupon rate on notes outstanding	4.61%	4.61%
Fair value of debt outstanding	$35,197	$36,018

Summary_of_LongTerm_Debt_Outst

Summary of Long-Term Debt Outstanding (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Debt [Line Items]
Long-Term Debt Outstanding	$1,534,476		$1,514,870
Less: Current maturities of long-term debt	10,181		9,512
Total	1,524,295		1,505,358
4.61% July 2003 Senior Notes Due Fiscal 2016
Debt [Line Items]
Long-Term Debt Outstanding	35,000		35,000
3.28% September 2010 Senior Notes Due Fiscal 2016
Debt [Line Items]
Long-Term Debt Outstanding	42,500		42,500
3.90% September 2010 Senior Notes Due Fiscal 2018
Debt [Line Items]
Long-Term Debt Outstanding	44,500		44,500
3.95% September 2010 Senior Notes Due Fiscal 2018
Debt [Line Items]
Long-Term Debt Outstanding	25,000		25,000
4.12% September 2010 Senior Notes Due Fiscal 2019
Debt [Line Items]
Long-Term Debt Outstanding	25,000		25,000
4.17% September 2010 Senior Notes Due Fiscal 2019
Debt [Line Items]
Long-Term Debt Outstanding	25,000		25,000
4.33% September 2010 Senior Notes Due Fiscal 2020
Debt [Line Items]
Long-Term Debt Outstanding	50,000		50,000
4.51% September 2010 Senior Notes Due Fiscal 2021
Debt [Line Items]
Long-Term Debt Outstanding	100,000		100,000
4.56% September 2010 Senior Notes Due Fiscal 2021
Debt [Line Items]
Long-Term Debt Outstanding	65,000		65,000
4.61% September 2010 Senior Notes Due Fiscal 2023
Debt [Line Items]
Long-Term Debt Outstanding	48,000		48,000
4.06% August 2011 Senior Notes Due Fiscal 2019
Debt [Line Items]
Long-Term Debt Outstanding	50,000		50,000
4.54% August 2011 Senior Notes Due Fiscal 2022
Debt [Line Items]
Long-Term Debt Outstanding	65,000		65,000
4.64% August 2011 Senior Notes Due Fiscal 2022
Debt [Line Items]
Long-Term Debt Outstanding	50,000		50,000
4.26% September 2013 senior notes due fiscal 2021
Debt [Line Items]
Long-Term Debt Outstanding	123,000		123,000
5.01% September 2013 senior notes due fiscal 2024
Debt [Line Items]
Long-Term Debt Outstanding	250,000		250,000
5.16% September 2013 senior notes due fiscal 2026
Debt [Line Items]
Long-Term Debt Outstanding	127,000		127,000
Norwegian Kroner Denominated Notes Due Fiscal Two Thousand Twenty Five
Debt [Line Items]
Long-Term Debt Outstanding	20,152		29,837
Norwegian Kroner Denominated Notes Due Fiscal Two Thousand Twenty Six
Debt [Line Items]
Long-Term Debt Outstanding	34,234		50,028
Norwegian Kroner Denominated Borrowing Agreement Due Fiscal Two Thousand Sixteen
Debt [Line Items]
Long-Term Debt Outstanding	2,490		5,837
Norwegian Kroner Denominated Borrowing Agreement Due Fiscal Two Thousand Nineteen
Debt [Line Items]
Long-Term Debt Outstanding	3,112		4,168
United States Dollar Denominated Borrowing Agreement Due Fiscal Two Thousand Twenty Seven
Debt [Line Items]
Long-Term Debt Outstanding	29,488
Term Loan Facility Due Twenty Nineteen
Debt [Line Items]
Term loan	300,000	[1]	300,000	[1]
Revolving Line Of Credit Due Fiscal Twenty Nineteen
Debt [Line Items]
Revolving line of credit	$20,000	[1]

[1]	In May 2015, the company amended its existing credit facility, extending the due dates of the bank term loan and revolving line of credit until fiscal 2020. Refer to Note (19) for additional information regarding the amended and extended credit facility.

Summary_of_LongTerm_Debt_Outst1

Summary of Long-Term Debt Outstanding (Parenthetical) (Detail)	12 Months Ended	0 Months Ended
	Mar. 31, 2015	27-May-15
4.61% July 2003 Senior Notes Due Fiscal 2016
Debt [Line Items]
Debt instrument interest rate	4.61%
Debt Instrument Maturity Period	Fiscal 2016
3.28% September 2010 Senior Notes Due Fiscal 2016
Debt [Line Items]
Debt instrument interest rate	3.28%
Debt Instrument Maturity Period	Fiscal 2016
3.90% September 2010 Senior Notes Due Fiscal 2018
Debt [Line Items]
Debt instrument interest rate	3.90%
Debt Instrument Maturity Period	Fiscal 2018
3.95% September 2010 Senior Notes Due Fiscal 2018
Debt [Line Items]
Debt instrument interest rate	3.95%
Debt Instrument Maturity Period	Fiscal 2018
4.12% September 2010 Senior Notes Due Fiscal 2019
Debt [Line Items]
Debt instrument interest rate	4.12%
Debt Instrument Maturity Period	Fiscal 2019
4.17% September 2010 Senior Notes Due Fiscal 2019
Debt [Line Items]
Debt instrument interest rate	4.17%
Debt Instrument Maturity Period	Fiscal 2019
4.33% September 2010 Senior Notes Due Fiscal 2020
Debt [Line Items]
Debt instrument interest rate	4.33%
Debt Instrument Maturity Period	Fiscal 2020
4.51% September 2010 Senior Notes Due Fiscal 2021
Debt [Line Items]
Debt instrument interest rate	4.51%
Debt Instrument Maturity Period	Fiscal 2021
4.56% September 2010 Senior Notes Due Fiscal 2021
Debt [Line Items]
Debt instrument interest rate	4.56%
Debt Instrument Maturity Period	Fiscal 2021
4.61% September 2010 Senior Notes Due Fiscal 2023
Debt [Line Items]
Debt instrument interest rate	4.61%
Debt Instrument Maturity Period	Fiscal 2023
4.06% August 2011 Senior Notes Due Fiscal 2019
Debt [Line Items]
Debt instrument interest rate	4.06%
Debt Instrument Maturity Period	Fiscal 2019
4.54% August 2011 Senior Notes Due Fiscal 2022
Debt [Line Items]
Debt instrument interest rate	4.54%
Debt Instrument Maturity Period	Fiscal 2022
4.64% August 2011 Senior Notes Due Fiscal 2022
Debt [Line Items]
Debt instrument interest rate	4.64%
Debt Instrument Maturity Period	Fiscal 2022
4.26% September 2013 senior notes due fiscal 2021
Debt [Line Items]
Debt instrument interest rate	4.26%
Debt Instrument Maturity Period	Fiscal 2021
5.01% September 2013 senior notes due fiscal 2024
Debt [Line Items]
Debt instrument interest rate	5.01%
Debt Instrument Maturity Period	Fiscal 2024
5.16% September 2013 senior notes due fiscal 2026
Debt [Line Items]
Debt instrument interest rate	5.16%
Debt Instrument Maturity Period	Fiscal 2026
Norwegian Kroner Denominated Notes Due Fiscal Two Thousand Twenty Five
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2025
Norwegian Kroner Denominated Notes Due Fiscal Two Thousand Twenty Six
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2026
Norwegian Kroner Denominated Borrowing Agreement Due Fiscal Two Thousand Sixteen
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2016
Norwegian Kroner Denominated Borrowing Agreement Due Fiscal Two Thousand Nineteen
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2019
United States Dollar Denominated Borrowing Agreement Due Fiscal Two Thousand Twenty Seven
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2027
Revolving Line Of Credit Due Fiscal Twenty Nineteen
Debt [Line Items]
Debt Instrument Maturity Period	Fiscal 2019
Subsequent Event \| Term Loan and Revolving Credit Facility
Debt [Line Items]
Debt Instrument Maturity Period		Fiscal 2020

Debt_Costs_Detail

Debt Costs (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Debt [Line Items]
Interest and debt costs incurred, net of interest capitalized	$50,029	$43,814	$29,745
Interest costs capitalized	13,673	11,497	10,602
Total interest and debt costs	$63,702	$55,311	$40,347

Employee_Retirement_Plans_Addi

Employee Retirement Plans - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended			3 Months Ended
	Dec. 31, 2010	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012
	Person	Person	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Number of employers participated in defined benefit plan	60
Number of employers still remains in defined benefit plan		45
Percentage of defined benefit plan, actuarial discount rate assumption		4.00%
Defined benefit plan, significant concentrations of risk		The pension plan and the supplemental plan assets are periodically evaluated for concentration risks. As of March 31, 2015, the company did not have any individual asset investments that comprised 10% or more of each plan's overall assets.
Defined benefit plan, concentration risk, assets, debt securities, maximum single issuer		5.00%
Defined benefit plan, concentration risk, assets, debt securities, maximum value single issuer		$2,500,000
Defined benefit plan, concentration risk, assets, equity securities, difference plan assets and liabilities		15.00%
Defined benefit plan, concentration risk, assets, equity securities, maximum single investment		5.00%
Defined benefit plan, concentration risk, assets, equity securities, maximum foreign and us stock		10.00%
Defined benefit plan, concentration risk, diversification, equity limit, single industry		25.00%
Defined benefit plan, concentration risk, diversification, equity limit, single corporation		10.00%
Defined benefit plan, concentration risk, diversification, debt limit, single issuer		10.00%
Retirement Contributions
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage		3.00%
Defined contribution plan, company contribution, vesting period, years		5
Retirement Contributions \| Minimum
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage additional percentage		1.00%
Retirement Contributions \| Maximum
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage additional percentage		8.00%
Defined Contribution Pension Plan 401k
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution, vesting period, years		5
Percentage of defined plan, minimum employee contribution		2.00%
Percentage of defined plan, maximum employee contribution		75.00%
Defined contribution plan, company contribution percentage match, common stock		50.00%
Defined contribution plan, company contribution percentage match, common stock		8.00%
Non-Qualified Supplemental Savings Plan Executives
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage match, common stock		50.00%
Deferred compensation arrangement with individual, deferred compensation percentage		50.00%
Deferred compensation arrangement with individual, deferred bonus percentage		100.00%
Defined contribution plan, restoration benefit		3.00%
Non-Qualified Supplemental Savings Plan Executives \| Minimum
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage additional percentage		1.00%
Non-Qualified Supplemental Savings Plan Executives \| Maximum
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution percentage additional percentage		8.00%
Multinational Pension Savings Plan
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined contribution plan, company contribution, vesting period, years		6
Percentage of defined plan, minimum employee contribution		1.00%
Percentage of defined plan, maximum employee contribution		15.00%
Percentage of defined plan, company contribution match, cash		50.00%
Percentage of defined plan, company contribution match, employee deferred compensation		6.00%
Pension Plans, Defined Benefit
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined benefit plan, employer contributions			0	0
Supplemental Executive Retirement Plan
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Defined benefit plan, employer contributions		0	0
Chief Executive Officer
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Distribution in settlement of plan obligation					13,000,000
Settlement loss recognized				($5,200,000)	$5,200,000

Schedule_of_Carrying_Value_of_

Schedule of Carrying Value of Trust Assets, Including Unrealized Gains or Losses (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Investments held in Rabbi Trust	$9,915	$10,285
Unrealized (loss) gains in carrying value of trust assets	235	92
Unrealized (loss) gains in carrying value of trust assets are net of income tax expense of	126	49
Obligations under the supplemental plan	$25,510	$21,918

Summary_of_Minimum_And_Maximum

Summary of Minimum And Maximum Rate of Return of Plan Assets (Detail) (Supplemental Executive Retirement Plan)	12 Months Ended
	Mar. 31, 2015
Minimum \| Equity Securities
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	5.00%
Minimum \| Debt Securities
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	1.00%
Minimum \| Cash and Cash Equivalents
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	0.00%
Maximum \| Equity Securities
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	7.00%
Maximum \| Debt Securities
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	3.00%
Maximum \| Cash and Cash Equivalents
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Expected Rate of Return on Plan Assets	1.00%

Schedule_of_Minimum_and_Maximu

Schedule of Minimum and Maximum Market Value of Plan Assets (Detail)	12 Months Ended
	Mar. 31, 2015
Equity Securities
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Minimum market value objective for plan assets	55.00%
Maximum market value objective for plan assets	75.00%
Debt Securities
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Minimum market value objective for plan assets	25.00%
Maximum market value objective for plan assets	45.00%
Investment Grade Bonds
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Minimum market value objective for plan assets	0.00%
Maximum market value objective for plan assets	20.00%
Cash and Cash Equivalents
Schedule of Pension and Other Postretirment Plan Assets by Fair Value [Line Items]
Minimum market value objective for plan assets	0.00%
Maximum market value objective for plan assets	10.00%

Schedule_of_Asset_Allocation_D

Schedule of Asset Allocation (Detail)	12 Months Ended
Schedule of Asset Allocation (Detail)	Mar. 31, 2015	Mar. 31, 2014
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	100.00%
Actual asset allocations	100.00%	100.00%
Pension Plans, Defined Benefit \| Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	100.00%
Actual asset allocations	95.00%	96.00%
Pension Plans, Defined Benefit \| Cash And Other
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocations	5.00%	4.00%
Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	100.00%
Actual asset allocations	100.00%	100.00%
Supplemental Executive Retirement Plan \| Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	65.00%
Actual asset allocations	58.00%	60.00%
Supplemental Executive Retirement Plan \| Debt Securities
Defined Benefit Plan Disclosure [Line Items]
Target asset allocation	35.00%
Actual asset allocations	39.00%	37.00%
Supplemental Executive Retirement Plan \| Cash And Other
Defined Benefit Plan Disclosure [Line Items]
Actual asset allocations	3.00%	3.00%

Schedule_of_Fair_Value_Assets_

Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	($59,485)	($56,896)
Total fair value of plan assets		10,285
Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	58,619	56,002
Accrued income	866	894
Total fair value of plan assets	59,485	56,896
Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	10,038	10,375
Other pending transactions	-123	-90
Total fair value of plan assets	9,915
US Government Agencies Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	3,116	2,935
US Government Agencies Debt Securities \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,926	1,975
Corporate Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	51,758	50,113
Foreign Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,529	1,443
Cash and Cash Equivalents \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,816	1,511
Cash and Cash Equivalents \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	377	369
Common stock \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	3,859	4,141
Foreign Stock \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	201	231
American Depository Receipts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,685	1,809
Preferred American Depository Receipts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	15	15
Real Estate Investment Trusts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	59	38
Open Ended Mutual Funds \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,916	1,797
Collateralized mortgage securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	400
Quoted Prices In Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total fair value of plan assets		9,361
Quoted Prices In Active Markets (Level 1) \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	3,116	2,935
Accrued income	866	894
Total fair value of plan assets	3,982	3,829
Quoted Prices In Active Markets (Level 1) \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	9,184	9,451
Other pending transactions	-123	-90
Total fair value of plan assets	9,061
Quoted Prices In Active Markets (Level 1) \| US Government Agencies Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	3,116	2,935
Quoted Prices In Active Markets (Level 1) \| US Government Agencies Debt Securities \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,377	1,363
Quoted Prices In Active Markets (Level 1) \| Cash and Cash Equivalents \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	72	57
Quoted Prices In Active Markets (Level 1) \| Common stock \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	3,859	4,141
Quoted Prices In Active Markets (Level 1) \| Foreign Stock \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	201	231
Quoted Prices In Active Markets (Level 1) \| American Depository Receipts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,685	1,809
Quoted Prices In Active Markets (Level 1) \| Preferred American Depository Receipts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	15	15
Quoted Prices In Active Markets (Level 1) \| Real Estate Investment Trusts \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	59	38
Quoted Prices In Active Markets (Level 1) \| Open Ended Mutual Funds \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,916	1,797
Significant Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Total fair value of plan assets		924
Significant Observable Inputs (Level 2) \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	55,503	53,067
Total fair value of plan assets	55,503	53,067
Significant Observable Inputs (Level 2) \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	854	924
Total fair value of plan assets	854
Significant Observable Inputs (Level 2) \| US Government Agencies Debt Securities \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	549	612
Significant Observable Inputs (Level 2) \| Corporate Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	51,758	50,113
Significant Observable Inputs (Level 2) \| Foreign Debt Securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,529	1,443
Significant Observable Inputs (Level 2) \| Cash and Cash Equivalents \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	1,816	1,511
Significant Observable Inputs (Level 2) \| Cash and Cash Equivalents \| Supplemental Executive Retirement Plan
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	305	312
Significant Observable Inputs (Level 2) \| Collateralized mortgage securities \| Pension Plans, Defined Benefit
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of plan assets	$400

Change_in_Plan_Assets_and_Obli

Change in Plan Assets and Obligations (Detail) (USD $)	12 Months Ended
Change in Plan Assets and Obligations (Detail) (USD $)	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2015
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Fair value of plan assets	$56,896,000		$59,485,000
Benefit obligation	-84,067,000		-96,308,000
Fair value of plan assets at end of year	56,896,000		59,485,000
Benefit obligation at end of year	84,067,000		96,308,000
Pension Plans, Defined Benefit
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Fair value of plan assets	-56,002,000		-58,619,000
Employer contributions	0	0
Fair value of plan assets at end of year	-56,002,000		-58,619,000
Current liabilities	-1,162,000		-1,306,000
Noncurrent liabilities	-26,009,000		-35,517,000
Net amount recognized	-27,171,000		-36,823,000
Pension Plans, Defined Benefit \| Change in Benefit Obligations
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Benefit obligation at beginning of year	88,238,000		84,067,000
Service cost	790,000		825,000
Benefit obligation	-84,067,000		-96,308,000
Interest cost	3,581,000		3,873,000
Plan settlement	0		0
Benefits paid	-4,250,000		-4,405,000
Actuarial (gain) loss	-4,292,000		11,948,000
Benefit obligation at end of year	84,067,000		96,308,000
Pension Plans, Defined Benefit \| Change in Plan Assets
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Fair value of plan assets at beginning of year	59,431,000		56,896,000
Fair value of plan assets	56,896,000		59,485,000
Actual return	776,000		6,069,000
Employer contributions	939,000		925,000
Plan settlement	0		0
Benefits paid	-4,250,000		-4,405,000
Fair value of plan assets at end of year	56,896,000		59,485,000
Pension Plans, Defined Benefit \| Reconciliation of Funded Status
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Fair value of plan assets	56,896,000		59,485,000
Benefit obligation	84,067,000		96,308,000
Unfunded status	-27,171,000		-36,823,000
Fair value of plan assets at end of year	56,896,000		59,485,000
Benefit obligation at end of year	-84,067,000		-96,308,000
Other Pension Plans, Defined Benefit
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Current liabilities	-1,129,000		-908,000
Noncurrent liabilities	-22,985,000		-23,018,000
Net amount recognized	-24,114,000		-23,926,000
Other Pension Plans, Defined Benefit \| Change in Benefit Obligations
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Benefit obligation at beginning of year	29,006,000		24,114,000
Service cost	405,000		273,000
Benefit obligation	-24,114,000		-23,926,000
Interest cost	1,048,000		904,000
Participant contributions	436,000		430,000
ERRP reimbursement	-26,000
Plan settlement	0		0
Benefits paid	-962,000		-863,000
Actuarial (gain) loss	-5,793,000		-932,000
Benefit obligation at end of year	24,114,000		23,926,000
Other Pension Plans, Defined Benefit \| Change in Plan Assets
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Employer contributions	552,000		433,000
Participant contributions	436,000		430,000
ERRP reimbursement	-26,000
Plan settlement	0		0
Benefits paid	-962,000		-863,000
Other Pension Plans, Defined Benefit \| Reconciliation of Funded Status
Schedule of Pension and Other Postretirement Benefits Changes in Benefit Obligation and Fair Value of Plan Assets [Line Items]
Benefit obligation	24,114,000		23,926,000
Unfunded status	-24,114,000		-23,926,000
Benefit obligation at end of year	($24,114,000)		($23,926,000)

Schedule_of_Projected_and_Accu

Schedule of Projected and Accumulated Benefit Obligation (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Defined Benefit Plan Change in Benefit Obligation [Line Items]
Projected benefit obligation	$96,308	$84,067
Accumulated benefit obligation	$92,808	$81,223

Schedule_of_Accumulated_Benefi

Schedule of Accumulated Benefit Obligation in Excess of Plan Assets (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Schedule of Pension Plans with Accumulated and Projected Benefit Obligations in Excess of Plan Assets [Line Items]
Projected benefit obligation	$96,308	$84,067
Accumulated benefit obligation	92,808	81,223
Fair value of plan assets	$59,485	$56,896

Schedule_of_Net_Periodic_Benef

Schedule of Net Periodic Benefit Cost (Detail) (Pension Plan and Supplemental Plan, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Pension Plan and Supplemental Plan
Net Period Benefit Cost Assumptions [Line Items]
Service cost	$825	$790	$983
Interest cost	3,873	3,581	4,098
Expected return on plan assets	-2,741	-2,871	-2,748
Amortization of prior service cost	50	50	50
Recognized actuarial loss	988	1,103	1,648
Settlement loss			5,161
Net periodic pension cost	$2,995	$2,653	$9,192

Schedule_of_Net_Periodic_Benef1

Schedule of Net Periodic Benefit Cost for Postretirement Health Care and Life Insurance Plan (Detail) (Other Benefits, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Other Benefits
Net Period Benefit Cost Assumptions [Line Items]
Service cost	$273	$405	$475
Interest cost	904	1,048	1,235
Amortization of prior service cost	-2,032	-2,032	-2,032
Recognized actuarial loss	-1,299	-396
Net periodic pension cost	($2,154)	($975)	($322)

Schedule_of_Other_Changes_in_P

Schedule of Other Changes in Plan Assets and Benefit Obligation Recognized (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Pension Plans, Defined Benefit
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Net loss (gain)	$8,621	($2,196)
Settlement loss	0	0
Amortization of prior service cost	-50	-50
Amortization of net (loss) gain	-988	-1,103
Total recognized in other comprehensive income (loss)	7,583	-3,349
Net of tax	7,583	-2,177
Other Pension Plans, Defined Benefit
Schedule Of Accumulated Benefit Obligations In Excess Of Fair Value Of Plan Assets And Amounts Recognized In Balance Sheet And In Other Comprehensive Income Loss [Line Items]
Net loss (gain)	-932	-5,793
Settlement loss	0	0
Amortization of prior service cost	2,032	2,032
Amortization of net (loss) gain	1,299	395
Other		197
Total recognized in other comprehensive income (loss)	2,399	-3,169
Net of tax	$1,559	($2,060)

Schedule_of_Amounts_Recognized

Schedule of Amounts Recognized in Accumulated Other Comprehensive Income (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	$21,781
Unrecognized prior service cost (benefit)	36
Pre-tax amount included in accumulated other comprehensive loss (income)	21,817
Other Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial (gain) loss	-6,620
Unrecognized prior service cost (benefit)	-4,588
Pre-tax amount included in accumulated other comprehensive loss (income)	($11,208)

Schedule_of_Expected_Amounts_o

Schedule of Expected Amounts of Net Periodic Benefit Costs (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost (benefit)	($988)	($1,103)
Pension Plans, Defined Benefit \| Next Fiscal Year
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	-2,213
Unrecognized prior service cost (benefit)	-36
Other Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Unrecognized prior service cost (benefit)	1,299	395
Other Pension Plans, Defined Benefit \| Next Fiscal Year
Defined Benefit Plan Disclosure [Line Items]
Unrecognized actuarial loss	582
Unrecognized prior service cost (benefit)	$2,041

Schedule_of_Assumptions_Net_Be

Schedule of Assumptions, Net Benefit Obligation (Detail)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	4.75%
Rates of annual increase in compensation levels	3.00%	3.00%	3.00%
Other Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.00%	4.75%

Schedule_of_Assumptions_Net_Pe

Schedule of Assumptions, Net Periodic Benefit Costs (Detail)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Pension Plans, Defined Benefit
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Discount rate	4.75%	4.25%	4.75%
Expected long-term rate of return on assets	5.00%	5.00%	5.00%
Rates of annual increase in compensation levels	3.00%	3.00%	3.00%
Other Pension Plans, Defined Benefit
Schedule Of Defined Benefit Plans Disclosures [Line Items]
Discount rate	4.75%	4.25%	4.75%

Schedule_of_Expected_Benefit_P

Schedule of Expected Benefit Payments (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Pension Plans, Defined Benefit
Schedule of Pension Expected Future Benefit Payments [Line Items]
2016	$5,578
2017	5,818
2018	6,077
2019	6,343
2020	7,419
2021 - 2025	33,918
Total 10-year estimated future benefit payments	65,153
Other Pension Plans, Defined Benefit
Schedule of Pension Expected Future Benefit Payments [Line Items]
2016	908
2017	982
2018	1,046
2019	1,128
2020	1,187
2021 - 2025	6,501
Total 10-year estimated future benefit payments	$11,752

Assumed_Health_Care_Cost_Trend

Assumed Health Care Cost Trend Rates (Detail)	12 Months Ended
Assumed Health Care Cost Trend Rates (Detail)	Mar. 31, 2015
Pre Sixty Five Coverage
Schedule of Pension Expected Future Benefit Payments [Line Items]
Accumulated postretirement benefit obligation	7.90%
Net periodic postretirement benefit obligation	8.20%
Ultimate health care cost trend	4.50%
Ultimate year health care cost trend rate is achieved	2029
Net periodic postretirement benefit obligation March 31, 2016	7.90%
Post Sixty Five Coverage
Schedule of Pension Expected Future Benefit Payments [Line Items]
Accumulated postretirement benefit obligation	6.90%
Net periodic postretirement benefit obligation	6.90%
Ultimate health care cost trend	4.50%
Ultimate year health care cost trend rate is achieved	2029
Net periodic postretirement benefit obligation March 31, 2016	6.90%

OnePercentage_Rate_Change_in_A

One-Percentage Rate Change in Assumed Health Care Cost Trend Rates and Its Effects on Accumulated Postretirement Benefit Obligation (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Schedule of Pension Expected Future Benefit Payments [Line Items]
Defined benefit plan, effect of one percentage point increase on accumulated postretirement benefit obligation	$3,702
Defined benefit plan, effect of one percentage point increase on aggregate service and interest cost	170
Defined benefit plan, effect of one percentage point decrease on accumulated postretirement benefit obligation	2,978
Defined benefit plan, effect of one percentage point decrease on aggregate service and interest cost	$138

Number_of_Shares_of_Tidewater_

Number of Shares of Tidewater Common Stock Held by Plan (Detail) (Defined Contribution Pension Plan 401k)	Mar. 31, 2015	Mar. 31, 2014
Defined Contribution Pension Plan 401k
Defined Contribution Plan [Line Items]
Number of shares of Tidewater common stock held by 401(k) plan	299,256	273,662

Amounts_Charged_to_Expense_Rel

Amounts Charged to Expense Related to Defined Contribution Plans (Detail) (Defined Contribution Pension Plan 401k, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Defined Contribution Pension Plan 401k
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plans expense, net of forfeitures	$4,216	$3,854	$3,356
Defined contribution plans forfeitures	$52	$82	$115

Amounts_Changed_to_Expense_Rel

Amounts Changed to Expense Related to Continue Plans (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Multinational pension savings plan expense	$494	$465	$420

Schedule_of_Other_Assets_Detai

Schedule of Other Assets (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Assets, Accrued Expenses, Other Current Liabilities, And Other Liabilities And Deferred Credits [Abstract]
Recoverable insurance losses	$10,468	$5,219
Deferred income tax assets	19,004	34,376
Deferred finance charges - revolver	7,396	8,728
Savings plans and supplemental plan	23,208	23,212
Noncurrent tax receivable		9,106
Other	15,120	15,744
Total other assets	$75,196	$96,385

Schedule_of_Accrued_Expenses_D

Schedule of Accrued Expenses (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Assets, Accrued Expenses, Other Current Liabilities, And Other Liabilities And Deferred Credits [Abstract]
Payroll and related payables	$32,041	$27,248
Commissions payable	8,282	8,263
Accrued vessel expenses	79,549	96,468
Accrued interest expense	14,514	14,816
Other accrued expenses	11,869	10,507
Accrued expenses	$146,255	$157,302

Schedule_of_Other_Current_Liab

Schedule of Other Current Liabilities (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Assets, Accrued Expenses, Other Current Liabilities, And Other Liabilities And Deferred Credits [Abstract]
Taxes payable	$56,620	$56,080
Deferred gain on vessel sales - current	25,057	13,996
Other	784	491
Other current liabilities	$82,461	$70,567

Schedule_of_Other_Liabilities_

Schedule of Other Liabilities and Deferred Credits (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Assets, Accrued Expenses, Other Current Liabilities, And Other Liabilities And Deferred Credits [Abstract]
Postretirement benefits liability	$23,018	$23,185
Pension liabilities	41,279	35,234
Deferred gain on vessel sales	136,238	85,316
Other	34,573	35,469
Other liabilities and deferred credits	$235,108	$179,204

Schedule_of_Common_Stock_Share

Schedule of Common Stock Shares Reserved for Issuance and Shares Available for Grant (Detail)	Mar. 31, 2015
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Shares of common stock reserved for issuance under the plans	2,580,880
Shares of common stock available for future grants	871,674

StockBased_Compensation_and_In2

Stock-Based Compensation and Incentive Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2015	Mar. 31, 2012
	D	Installment
		D
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding	1,370,056	1,556,275	1,709,206	1,725,424
Intrinsic value of options outstanding			0
Intrinsic value of options exercisable			0
Fair value of non-vested shares	$48.68	$50.48	39.53	$50.56
Director stock payment period, units	15	15
Optional payment installments, annual		15
Director
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of stock units granted	115,000	100,000
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period			3 months
Optional payment installments, annual	2
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option expiration period			10 years
Optional payment installments, annual	10
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General vesting period, years			3 years
Post retirement period to exercise vested options			2 years
Total unrecognized stock compensation costs			2,300,000
Total unrecognized stock compensation costs, net of tax			1,300,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock compensation costs			500,000
Total unrecognized stock compensation costs, net of tax			500,000
Time-based stock vesting period, years			4
Fair value of non-vested shares	$54.75	$50.95	56.94	$51.43
Restricted Stock \| Time Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation outstanding number			24,291
Restricted Stock \| Performance Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation outstanding number			68,405
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock compensation costs			16,600,000
Total unrecognized stock compensation costs, net of tax			11,400,000
Restricted Stock Units (RSUs) \| Time Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation outstanding number			156,772
Restricted Stock Units (RSUs) \| Performance Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation outstanding number			92,194
Phantom Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock compensation costs			13,400,000
Total unrecognized stock compensation costs, net of tax			10,800,000
Fair value of non-vested shares	$50.94	$51.74	24.07	$49.23
Phantom Stock Plan \| Time Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation outstanding number			196,047
Phantom Stock Plan \| Non-Vested Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of non-vested shares			19.14
Phantom Stock Plan \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General vesting period, years			3 years
Phantom Stock Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
General vesting period, years			4 years
Cash-based Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized stock compensation costs			4,900,000
Total unrecognized stock compensation costs, net of tax			3,300,000
Share based compensation outstanding number			0
Fair value of non-vested shares			1.1
Cash-based Performance Plan \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Units awarded, vesting rights amount			2

Fair_Value_and_Assumptions_Use

Fair Value and Assumptions Used For Stock Options Issued (Detail) (USD $)	12 Months Ended
	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value of stock options granted	$5.54
Risk-free interest rate	1.82%
Expected dividend yield	2.40%
Expected stock price volatility	30.00%
Expected stock option life	6 years 6 months

Summary_of_Stock_Option_Activi

Summary of Stock Option Activity (Detail) (USD $)	12 Months Ended
Summary of Stock Option Activity (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Stock-Based Compensation And Incentive Plans [Abstract]
Weighted-average Exercise Price Beginning Balance Outstanding	$47.51	$46.24	$44.93
Weighted-average Exercise Price-Granted	$22.80
Weighted-average Exercise Price-Exercised	$35.21	$36.86	$29.09
Weighted-average Exercise Price-Expired or cancelled/forfeited	$42.97		$52.47
Weighted-average Exercise Price, Ending Balance Outstanding	$41.69	$47.51	$46.24
Number of Shares Outstanding
Number of Shares Beginning Balance Outstanding	1,370,056	1,556,275	1,725,424
Number of Shares-Granted	428,326
Number of Shares-Exercised	-29,118	-186,219	-141,542
Number of Shares-Expired or cancelled/forfeited	-60,058		-27,607
Number of Shares Ending Balance Outstanding	1,709,206	1,370,056	1,556,275

Options_Outstanding_ExercisePr

Options Outstanding, Exercise-Price Ranges (Detail) (USD $)	12 Months Ended
Options Outstanding, Exercise-Price Ranges (Detail) (USD $)	Mar. 31, 2015
Exercise Price Range - $22.80 - $33.83
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range minimum	$22.80
Exercise price range maximum	$33.83
Options outstanding	728,287
Weighted average exercise price of options outstanding	$27.34
Weighted average remaining contractual life of options outstanding	7 years 6 months
Options exercisable	307,488
Weighted average exercise price of options exercisable	$33.56
Weighted average remaining contractual life of options exercisable	4 years 1 month 6 days
Exercise Price Range - $45.75 - $48.96
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range minimum	$45.75
Exercise price range maximum	$48.96
Options outstanding	394,515
Weighted average exercise price of options outstanding	$45.86
Weighted average remaining contractual life of options outstanding	5 years
Options exercisable	394,515
Weighted average exercise price of options exercisable	$45.86
Weighted average remaining contractual life of options exercisable	5 years
Exercise Price Range - $55.76 - $65.69
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range minimum	$55.76
Exercise price range maximum	$65.69
Options outstanding	586,404
Weighted average exercise price of options outstanding	$56.70
Weighted average remaining contractual life of options outstanding	2 years
Options exercisable	586,404
Weighted average exercise price of options exercisable	$56.70
Weighted average remaining contractual life of options exercisable	2 years

Additional_Information_Regardi

Additional Information Regarding Stock Options (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Intrinsic value of options exercised	$475	$4,059	$2,544
Number of stock options vested	7,527	8,926	144,537
Fair value of stock options vested	$40	$115	$2,154
Number of options exercisable	1,288,407	1,370,056	1,547,349
Weighted average exercise price of options exercisable	$47.86	$47.51	$46.27

Schedule_of_Stock_Option_Compe

Schedule of Stock Option Compensation Expense (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option compensation expense	$71	$12	$2,049
Basic earnings per share reduced by	$0	$0	$0.03
Diluted earnings per share reduced by	$0	$0	$0.03

Summary_of_Restricted_Stock_Aw

Summary of Restricted Stock Award Activity (Detail) (USD $)	12 Months Ended
Summary of Restricted Stock Award Activity (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$48.68	$50.48	$50.56
Weighted-average Grant-Date Fair Value-Granted	$19.14	$49.47	$50.48
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$39.53	$48.68	$50.48
Number of Shares Beginning Balance Outstanding	146,388	144,007	114,580
Number of Shares-Granted	56,370	26,550	26,955
Number of Shares Ending Balance Outstanding	185,060	146,388	144,007
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$54.75	$50.95	$51.43
Weighted-average Grant-Date Fair Value-Granted		$55.04
Weighted-average Grant-Date Fair Value-Vested	$57.46	$56.71	$49.53
Weighted-average Grant-Date Fair Value-Cancelled/forfeited	$47.09	$35.76	$56.84
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$56.94	$54.75	$50.95
Time Based Shares \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Beginning Balance Outstanding	78,824	148,549	266,418
Number of Shares-Granted		28,963
Number of Shares-Vested	-48,574	-93,739	-110,802
Number of Shares-Cancelled/forfeited	-5,959	-4,949	-7,067
Number of Shares Ending Balance Outstanding	24,291	78,824	148,549
Performance Based Shares \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Beginning Balance Outstanding	106,266	164,138	223,641
Number of Shares-Vested		-1,749
Number of Shares-Cancelled/forfeited	-37,861	-56,123	-59,503
Number of Shares Ending Balance Outstanding	68,405	106,266	164,138

Schedule_of_Restricted_Stock_A

Schedule of Restricted Stock Award Compensation Expense and Grant Date Fair Value (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$71	$12	$2,049
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of restricted stock vested	2,791	4,671	5,488
Compensation expense	$2,855	$4,633	$5,987

Summary_of_Restricted_Stock_Ac

Summary of Restricted Stock Activity (Detail) (USD $)	12 Months Ended
Summary of Restricted Stock Activity (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$48.68	$50.48	$50.56
Weighted-average Grant-Date Fair Value, Granted	$19.14	$49.47	$50.48
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$39.53	$48.68	$50.48
Number of Shares Beginning Balance Outstanding	146,388	144,007	114,580
Number of Shares, Granted	56,370	26,550	26,955
Number of Shares Ending Balance Outstanding	185,060	146,388	144,007
Restricted Stock Units (RSUs) \| Time Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$50.24	$51.69	$54.18
Weighted-average Grant-Date Fair Value, Granted	$54.48	$49.37	$50.16
Weighted-average Grant-Date Fair Value, Vested	$50.92	$52.22	$54.17
Weighted-average Grant-Date Fair Value, Cancelled/forfeited	$49.62	$52.43	$54.18
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$49.50	$50.24	$51.69
Number of Shares Beginning Balance Outstanding	495,209	417,665	248,288
Number of Shares, Granted	551	265,937	259,158
Number of Shares, Vested	-237,229	-175,673	-79,507
Number of Shares, Cancelled/forfeited	-7,381	-12,720	-10,274
Number of Shares Ending Balance Outstanding	251,150	495,209	417,665
Restricted Stock Units (RSUs) \| Performance Based Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding		$69.62	$72.23
Weighted-average Grant-Date Fair Value, Granted		$56.44	$67.11
Weighted-average Grant-Date Fair Value, Cancelled/forfeited			$72.23
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$53.58	$53.58	$69.62
Number of Shares Beginning Balance Outstanding		165,241	84,394
Number of Shares, Granted		91,132	84,323
Number of Shares, Cancelled/forfeited			-3,476
Number of Shares Ending Balance Outstanding	256,373	256,373	165,241

Schedule_of_Restricted_Stock_U

Schedule of Restricted Stock Unit Compensation Expense And Grant Date Fair Value (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$71	$12	$2,049
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of restricted stock units vested	12,080	9,176	4,307
Compensation expense	$17,214	$12,664	$7,836

Summary_of_Phantom_Stock_Activ

Summary of Phantom Stock Activity (Detail) (USD $)	12 Months Ended
Summary of Phantom Stock Activity (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$48.68	$50.48	$50.56
Weighted-average Grant-Date Fair Value-Granted	$19.14	$49.47	$50.48
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$39.53	$48.68	$50.48
Number of Shares Beginning Balance Outstanding	146,388	144,007	114,580
Number of Shares-Granted	56,370	26,550	26,955
Number of Shares Ending Balance Outstanding	185,060	146,388	144,007
Phantom Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$50.94	$51.74	$49.23
Weighted-average Grant-Date Fair Value-Granted	$22.80	$48.81	$50.76
Weighted-average Grant-Date Fair Value-Vested	$48.47	$51.45	$43.60
Weighted-average Grant-Date Fair Value-Cancelled/forfeited	$50.70	$50.93	$54.26
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$24.07	$50.94	$51.74
Time Based Restricted Stock Awards \| Phantom Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Beginning Balance Outstanding	60,882	68,595	103,311
Number of Shares-Granted	546,058	31,736	27,100
Number of Shares-Vested	-33,987	-35,095	-54,823
Number of Shares-Cancelled/forfeited	-5,482	-4,354	-6,993
Number of Shares Ending Balance Outstanding	567,471	60,882	68,595
Performance Based Shares \| Phantom Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares Beginning Balance Outstanding			28,059
Number of Shares-Granted		1,291
Number of Shares-Cancelled/forfeited			-28,059
Number of Shares Ending Balance Outstanding	1,291	1,291

Schedule_of_Phantom_Stock_Comp

Schedule of Phantom Stock Compensation Expense And Grant Date Fair Value (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$71	$12	$2,049
Phantom Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of phantom stock vested	1,647	1,806	2,390
Compensation expense	933	1,706	2,507
Phantom stock compensation costs capitalized as part of an asset	$0	$0	$0

Summary_of_CashBased_Performan

Summary of Cash-Based Performance Plan Unit Activity (Detail) (USD $)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$48.68	$50.48	$50.56
Weighted-average Grant-Date Fair Value, Granted	$19.14	$49.47	$50.48
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$39.53	$48.68	$50.48
Number of Shares Beginning Balance Outstanding	146,388	144,007	114,580
Number of Shares, Granted	56,370	26,550	26,955
Number of Shares Ending Balance Outstanding	185,060	146,388	144,007
Cash-based Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average Grant-Date Fair Value, Granted	$1.10
Weighted-average Grant-Date Fair Value, Vested	$0
Weighted-average Grant-Date Fair Value, Cancelled/forfeited	$0
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$1.10
Number of Shares, Granted	4,519,703
Number of Shares, Vested	0
Number of Shares, Cancelled/forfeited	0
Number of Shares Ending Balance Outstanding	4,519,703

Schedule_of_Restricted_Stock_C

Schedule of Restricted Stock Compensation Expense and Grant Date Fair Value (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$71	$12	$2,049
Cash-based Performance Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value of cash-based performance units	0
Compensation expense	$72

Summary_of_Deferred_Stock_Unit

Summary of Deferred Stock Unit Activity (Detail) (USD $)	12 Months Ended
Summary of Deferred Stock Unit Activity (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Weighted-average Grant-Date Fair Value, Beginning Balance Outstanding	$48.68	$50.48	$50.56
Weighted-average Grant-Date Fair Value-Dividend equivalents reinvested	$34.63	$53.82	$46.73
Weighted-average Grant-Date Fair Value-Retirement distribution	$47.50	$59.65
Weighted-average Grant-Date Fair Value-Granted	$19.14	$49.47	$50.48
Weighted-average Grant-Date Fair Value, Ending Balance Outstanding	$39.53	$48.68	$50.48
Number of Shares Beginning Balance Outstanding	146,388	144,007	114,580
Number of Shares-Dividend equivalents reinvested	3,794	2,492	2,472
Number of Shares-Retirement distribution	-21,492	-26,661
Number of Shares-Granted	56,370	26,550	26,955
Number of Shares Ending Balance Outstanding	185,060	146,388	144,007

Schedule_of_Deferred_Stock_Uni

Schedule of Deferred Stock Unit Compensation Expense (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense (benefit)	$21,374	$19,642	$19,416
Deferred Stock Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense (benefit)	($2,477)	$1,737	$1,085

Schedule_of_Authorized_And_Iss

Schedule of Authorized And Issued Common Stock And Preferred Stock (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
Stockholders' Equity [Abstract]
Common stock shares authorized	125,000,000	125,000,000
Common stock par value	$0.10	$0.10
Common stock shares issued	47,029,359	49,730,442
Preferred stock shares authorized	3,000,000	3,000,000
Preferred stock par value
Preferred stock shares issued	0	0

Stockholders_Equity_Additional

Stockholders' Equity - Additional Information (Detail) (USD $)	12 Months Ended		3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	31-May-14	Mar. 31, 2013
Stockholders Equity Note [Line Items]
Amount remaining authorized to repurchase shares	$100		100
September 2010 Senior Unsecured Notes
Stockholders Equity Note [Line Items]
Accumulated other comprehensive loss related to hedges, after-tax loss relating to interest rate hedges	1.8	2.4
Accumulated other comprehensive loss related to hedges, pre-tax loss relating to interest rate hedges	2.6	3.7
May 2014 Authorized Amount
Stockholders Equity Note [Line Items]
Amount remaining authorized to repurchase shares	100		100
Amount authorized to repurchase shares				200
May 2013 Authorized Amount
Stockholders Equity Note [Line Items]
Amount authorized to repurchase shares					200
Number of Shares Authorized to be Repurchased			0
May Two Thousand Fifteen Authorized Amount
Stockholders Equity Note [Line Items]
Amount remaining authorized to repurchase shares	$100		100

Schedule_of_Common_Stock_Repur

Schedule of Common Stock Repurchased and Average Price Paid Per Share (Detail) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2013
Stockholders' Equity [Abstract]
Aggregate cost of common stock repurchased	$99,999	$85,034
Shares of common stock repurchased	2,841,976	1,856,900
Average price paid per common share	$35.19	$45.79

Schedule_of_Dividends_Declared

Schedule of Dividends Declared (Detail) (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Stockholders' Equity [Abstract]
Dividends declared	$49,127	$49,973	$49,766
Dividend per share	$1	$1	$1

Changes_in_Accumulated_Other_C

Changes in Accumulated Other Comprehensive Income by Component, Net of Tax (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	($12,225)	($17,141)
Gains/(losses) recognized in OCI	-9,077	4,145
Reclasses from OCI to net income	924	771
Net period OCI	-8,153	4,916
Accumulated other comprehensive income, ending balance	-20,378	-12,225
Available for Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	92	-121
Gains/(losses) recognized in OCI	-64	-92
Reclasses from OCI to net income	207	305
Net period OCI	143	213
Accumulated other comprehensive income, ending balance	235	92
Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance			-9,811
Accumulated other comprehensive income, ending balance	-9,811	-9,811	-9,811
Pension/Post-retirement Benefits
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	-116	-4,353
Gains/(losses) recognized in OCI	-9,013	4,237
Net period OCI	-9,013	4,237
Accumulated other comprehensive income, ending balance	-9,129	-116
Interest Rate Swap
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income, beginning balance	-2,390	-2,856
Reclasses from OCI to net income	717	466
Net period OCI	717	466
Accumulated other comprehensive income, ending balance	($1,673)	($2,390)

Reclassifications_from_Accumul

Reclassifications from Accumulated Other Comprehensive Loss to Condensed Consolidated Statement of Income (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	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, 2015	Mar. 31, 2014	Mar. 31, 2013
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income and other, net									$1,927	$2,123	$3,476
Interest and other debt costs									-50,029	-43,814	-29,745
Total pre-tax amounts									-66,267	173,048	195,163
Tax effect									-1,077	32,793	44,413
Net earnings (loss) attributable to Tidewater Inc.	-9,076	-160,694	60,907	43,673	43,417	12,583	54,172	30,083	-65,190	140,255	150,750
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total pre-tax amounts									924	1,186
Tax effect										415
Net earnings (loss) attributable to Tidewater Inc.									924	771
Reclassification out of Accumulated Other Comprehensive Income \| Available for Sale Securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest income and other, net									207	469
Reclassification out of Accumulated Other Comprehensive Income \| Interest Rate Swap
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Interest and other debt costs									$717	$717

Components_of_Basic_and_Dilute

Components of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Share data, unless otherwise specified	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, 2015	Mar. 31, 2014	Mar. 31, 2013
Schedule Of Earnings Per Share Basic And Diluted [Line Items]
Net earnings (loss) available to common shareholders (A)	($9,076)	($160,694)	$60,907	$43,673	$43,417	$12,583	$54,172	$30,083	($65,190)	$140,255	$150,750
Weighted average outstanding shares of common stock, basic (B)									48,658,840	49,392,749	49,550,391
Dilutive effect of options and restricted stock awards										287,365	183,649
Weighted average common stock and equivalents (C)									48,658,840	49,680,114	49,734,040
Earnings per share, basic (A/B)	($0.19)	($3.31)	$1.23	$0.88	$0.88	$0.25	$1.10	$0.61	($1.34)	$2.84	$3.04
Earnings per share, diluted (A/C)	($0.19)	($3.31)	$1.22	$0.88	$0.88	$0.25	$1.09	$0.61	($1.34)	$2.82	$3.03
Antidilutive options and restricted stock shares									284,635	34,486	82,758

Details_of_Number_of_Vessels_T

Details of Number of Vessels, Total Proceeds, Carrying Values at the Time of Sale, Deferred Gains Recognized, Lease Expirations, and Contractual Purchase Option (Detail) (USD $)	1 Months Ended					3 Months Ended							12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Jul. 31, 2009	Jun. 30, 2009	Mar. 31, 2006	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2010
	Vessel	Vessel	Vessel	Vessel	Mar. 31, 2006	Vessel	Vessel	Vessel	Vessel	Vessel	Vessel	Vessel	Vessel	Vessel	Mar. 31, 2010
Sale Leaseback Transaction [Line Items]
Number of Vessels	2	3	6	6		1	3	1	1	4	4	2	6	10
Total Proceeds					$76,500	$13,000	$78,200	$19,350	$13,400	$63,305	$141,900	$65,550	$123,950	$270,755	$101,800
Carrying Value at time of Sale						5,115	33,233	8,214	4,002	32,845	105,649	34,325	50,564	172,819
Deferred Gain at time of Sale						$7,885	$44,967	$11,136	$9,398	$30,460	$36,251	$31,225	$73,386	$97,936
Lease Term in Years						7 years		8 years 6 months	7 years			7 years
Purchase Option Percentage						50.00%	60.00%	47.00%	61.00%			55.00%
Purchase Option at end of:						6thYear	7th or 8th Year	8thYear	6th Year	6th or 9th Year	6th or 8th Year	6th Year
Minimum
Sale Leaseback Transaction [Line Items]
Lease Term in Years							8 years			7 years	7 years
Purchase Option Percentage										53.00%	54.00%
Maximum
Sale Leaseback Transaction [Line Items]
Lease Term in Years							9 years			10 years	9 years
Purchase Option Percentage										59.00%	68.00%

Sale_Leaseback_Arrangements_Ad

Sale/ Leaseback Arrangements - Additional Information (Detail) (USD $)

1 Months Ended

3 Months Ended

12 Months Ended

1 Months Ended

Mar. 31, 2015

Mar. 31, 2014

Jul. 31, 2009

Jun. 30, 2009

Mar. 31, 2006

Mar. 31, 2015

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Mar. 31, 2015

Mar. 31, 2014

Mar. 31, 2010

Mar. 31, 2006

Nov. 30, 2014

Sep. 30, 2012

Oct. 31, 2012

Vessel

Entity

Vessel

Leases

Vessel

Leases

Sale Leaseback Transaction [Line Items]

Number of vessels sold

Number of unrelated third-party companies

Proceeds from sale

$76,500,000

$13,000,000

$78,200,000

$19,350,000

$13,400,000

$63,305,000

$141,900,000

$65,550,000

$123,950,000

$270,755,000

$101,800,000

Deferred gain

39,600,000

Carrying value

62,200,000

Charter hire operating lease terms

5 years

Repurchase of leased vessels

78,800,000

Number of vessels to be sold that are under construction

Number of Operating Lease

Length of extension period, years

8 years

Third and Fourth PSV

Sale Leaseback Transaction [Line Items]

Repurchase of leased vessels

22,800,000

Fifth Vessel

Sale Leaseback Transaction [Line Items]

Repurchase of leased vessels

11,200,000

First PSV

Sale Leaseback Transaction [Line Items]

Repurchase of leased vessels

8,800,000

Second PSV

Sale Leaseback Transaction [Line Items]

Repurchase of leased vessels

$8,400,000

Schedule_of_Future_Minimum_Lea

Schedule of Future Minimum Lease Payments (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified	Mar. 31, 2015
Sale Leaseback Transaction [Line Items]
2016	$30,364
2017	30,364
2018	33,090
2019	35,034
2020	37,016
Thereafter	70,610
Total future lease payments	236,478
Fiscal 2015 Sale/Leasebacks
Sale Leaseback Transaction [Line Items]
2016	9,485
2017	9,485
2018	9,605
2019	10,234
2020	11,497
Thereafter	30,866
Total future lease payments	81,172
Fiscal 2014 Sale/Leasebacks
Sale Leaseback Transaction [Line Items]
2016	20,879
2017	20,879
2018	23,485
2019	24,800
2020	25,519
Thereafter	39,744
Total future lease payments	$155,306

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Mar. 31, 2015	Mar. 31, 2013
	Vessel	T	Vessel
Significant Purchase and Supply Commitment [Line Items]
Cash compensation on termination of employment, maximum		43
Number of Vessels, commitments		21
Towing Supply Vessels
Significant Purchase and Supply Commitment [Line Items]
Significant commitment, new construction brake horsepower		7,145
Deepwater PSVs
Significant Purchase and Supply Commitment [Line Items]
Significant commitment, new construction deadweight tons capacity range, low		3,800
Significant commitment, new construction deadweight tons capacity range, high		6,000
Significant commitment, new construction final delivery date		Sep-16
Number of vessels took for delivery	2
Amount held as escrow	11.7
Number of vessels			2
Number of vessels, sold			1
Deferred gain amortization period			10 years
Fast, Crew/Supply Boat
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction		1
Insurance coverage for the progress payments made on the vessel by the third party credit support		90.00%
Insurance coverage by the third party credit support for the carrying value of the accumulated costs		2.4
Committed and invested amount		8

Schedule_of_Vessel_Commitments

Schedule of Vessel Commitments (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
	Vessel
Significant Purchase and Supply Commitment [Line Items]
Number of Vessels, commitments	21
Vessel Commitments
Significant Purchase and Supply Commitment [Line Items]
Number of Vessels, commitments	24
Total cost, commitments	$690,665
Invested, commitments	310,612
Remaining Balance, commitments	380,053
Deepwater PSVs
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction	17	[1]
Total cost, under construction	576,847	[1]
Invested, under construction	223,301	[1]
Remaining Balance, under construction	353,546	[1]
Towing Supply Vessels
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction	6	[1]
Total cost, under construction	105,804	[1]
Invested, under construction	79,297	[1]
Remaining Balance, under construction	26,507	[1]
Other
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction	1
Total cost, under construction	8,014
Invested, under construction	$8,014

[1]	In April 2015, the company cancelled the construction contracts for three towing-supply vessels. There were approximately $13 million of remaining costs to be incurred on these three vessels at the time of termination. In May 2015, the company and the Chinese shipyard that is constructing two 275-foot deepwater PSVs came to an agreement that provides the company an option to take delivery of one or both vessels at any time prior to June 30, 2016 or receive the return of installments aggregating $5.7 million per vessel at the end of this period. There were approximately $41 million of remaining costs to be incurred on these two vessels at the time of the agreement. Refer to Note (19) for a discussion of these vessel construction contract modifications.

Schedule_of_Vessel_Commitments1

Schedule of Vessel Commitments (Parenthetical) (Detail) (USD $)	12 Months Ended		1 Months Ended			2 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015		Apr. 30, 2015	27-May-15	31-May-15	27-May-15
	Vessel		Contract	27-May-15	Vessel	Vessel
Deepwater PSVs
Significant Purchase and Supply Commitment [Line Items]
Aggregate installment payment	$1,000
Towing Supply Vessels
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction	6	[1]
Aggregate installment payment	79,297	[1]
Aggregate estimated remaining cost	26,507	[1]
Subsequent Event
Significant Purchase and Supply Commitment [Line Items]
Number of vessels constructions terminated			3
Subsequent Event \| Deepwater PSVs
Significant Purchase and Supply Commitment [Line Items]
Number of vessels under construction					2	2
Significant commitment, new construction delivery date				30-Jun-16	30-Jun-16
Aggregate installment payment				5,400	5,700	5,400
Aggregate estimated remaining cost					41,000
Subsequent Event \| Commitment upon Contract Termination [Member]
Significant Purchase and Supply Commitment [Line Items]
Remaining Balance, commitments			13,000
Subsequent Event \| Towing Supply Vessels
Significant Purchase and Supply Commitment [Line Items]
Number of vessels constructions terminated			3

[1]	In April 2015, the company cancelled the construction contracts for three towing-supply vessels. There were approximately $13 million of remaining costs to be incurred on these three vessels at the time of termination. In May 2015, the company and the Chinese shipyard that is constructing two 275-foot deepwater PSVs came to an agreement that provides the company an option to take delivery of one or both vessels at any time prior to June 30, 2016 or receive the return of installments aggregating $5.7 million per vessel at the end of this period. There were approximately $41 million of remaining costs to be incurred on these two vessels at the time of the agreement. Refer to Note (19) for a discussion of these vessel construction contract modifications.

Commitments_and_Contingencies_2

Commitments and Contingencies (Merchant Navy Officers Pension Fund) - Additional Information (Detail) (Merchant Navy Officers Pension Fund)	0 Months Ended
	Jul. 15, 2013
	Vessel
Merchant Navy Officers Pension Fund
Commitments and Contingencies Disclosure [Line Items]
Number of Vessels to be purchased	7

Commitments_and_Contingencies_3

Commitments and Contingencies (Sonatide Joint Venture) - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013	Nov. 30, 2013	Dec. 31, 2014
	Vessel	Vessel	Mar. 31, 2013	Nov. 30, 2013	Dec. 31, 2014
Commitments and Contingencies Disclosure [Line Items]
Vessel revenues	$1,468,358,000	$1,418,461,000	$1,229,998,000
Number of vessels operating	263	272
Investments in, at equity, and advances to unconsolidated companies	65,844,000	63,928,000	46,047,000
Commissions payable	8,282,000	8,263,000
Minimum
Commitments and Contingencies Disclosure [Line Items]
Additional percentage of surcharges on foreign exchange transactions	10.00%
Maximum
Commitments and Contingencies Disclosure [Line Items]
Ownership Interest In Joint Venture	50.00%
Additional percentage of surcharges on foreign exchange transactions	20.00%
Expected time period to deliver the new build vessels	2 years
Sonatide joint venture
Commitments and Contingencies Disclosure [Line Items]
Definitive joint venture agreement term				2 years
Proceeds from related party	338,000,000
Proceeds from dividends received					10,000,000
Due from related parties	420,000,000
Number of vessels operating	10
Number of vessels stacked	3
Ownership Interest In Joint Venture	49.00%
Investments in, at equity, and advances to unconsolidated companies	67,000,000	62,000,000
Sonatide joint venture \| U.S. dollars initially received by Sonatide on behalf of the company or dollars collected from other customers
Commitments and Contingencies Disclosure [Line Items]
Proceeds from related party	159,000,000
Sonatide joint venture \| Sonatide's converting kwanza into dollars and subsequently expatriating the dollars to Tidewater
Commitments and Contingencies Disclosure [Line Items]
Proceeds from related party	179,000,000
Sonatide joint venture \| Trade and other receivables
Commitments and Contingencies Disclosure [Line Items]
Due from related parties	420,000,000	430,000,000
Sonatide joint venture \| Accrued expenses
Commitments and Contingencies Disclosure [Line Items]
Due to related parties	186,000,000	86,000,000
Commissions payable	66,000,000	43,000,000
Sonatide joint venture \| Kwanza-denominated deposits
Commitments and Contingencies Disclosure [Line Items]
Bank deposits maintained	150,000,000
Sonatide joint venture \| ANGOLA
Commitments and Contingencies Disclosure [Line Items]
Vessel revenues	$351,000,000	$357,000,000
Percentage of Angolan operation revenue	23.00%	25.00%
Number of vessels operating	80	90
Number of vessels stacked	8	5
Ownership percentage requirement of local vessel operators	100.00%
Number of vessels transferred out of Angola	13
Number of vessels stacked transferred	4
Sonatide joint venture \| ANGOLA \| Increase
Commitments and Contingencies Disclosure [Line Items]
Number of vessels operating		1

Commitments_and_Contingencies_4

Commitments and Contingencies (Brazilian Customs) - Additional Information (Detail)	1 Months Ended	12 Months Ended
In Millions, unless otherwise specified	Apr. 30, 2011	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2015	Mar. 31, 2015
	BRL	USD ($)	BRL	Revised	Revised
	Vessel			USD ($)	BRL
Commitments and Contingencies Disclosure [Line Items]
Fines assessed	155	$48.50		$39.70	127
Number of Tidewater vessels that the subsidiaries failed to obtain import licenses from	17
Disallowed amount of total fines by the administrative appeals board		46.6	149
Remaining amount of fines contested		8.8	28
Decision disallowing the fines totaling			127

Commitment_and_Contingencies_N

Commitment and Contingencies (Nigeria Marketing Agent Litigation) - Additional Information (Detail) (Federal Government of Nigeria, USD $)	Mar. 01, 2013
In Millions, unless otherwise specified	Mar. 01, 2013
Federal Government of Nigeria
Commitments and Contingencies Disclosure [Line Items]
Due to affiliates	$16

Commitment_and_Contingencies_A

Commitment and Contingencies (Aribitral Award for the Taking of the Company's Venezuelan Operations) - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Feb. 08, 2013	31-May-09	Jul. 31, 2009	Mar. 31, 2015
	Vessel	Vessel	Vessel	Mar. 31, 2015
Commitments and Contingencies Disclosure [Line Items]
Number of vessels seized	15
Venezuelan National Oil Company
Commitments and Contingencies Disclosure [Line Items]
Number of vessels seized		11
Petrosucre S
Commitments and Contingencies Disclosure [Line Items]
Number of vessels seized			4
Compensation for expropriation of the investments of subsidiaries \| VENEZUELA
Commitments and Contingencies Disclosure [Line Items]
Compensation awarded to the subsidiaries, annual compound interest rate				4.50%
Compensation for expropriation of the investments of subsidiaries \| VENEZUELA \| Fair market value of the Company's principal of the subsidiary
Commitments and Contingencies Disclosure [Line Items]
Compensation awarded to the subsidiaries				46.4
Compensation for expropriation of the investments of subsidiaries \| VENEZUELA \| Portion of compounded interest to date
Commitments and Contingencies Disclosure [Line Items]
Compensation awarded to the subsidiaries				13.9
Compensation for expropriation of the investments of subsidiaries \| VENEZUELA \| Reimbursement of legal and other costs expended
Commitments and Contingencies Disclosure [Line Items]
Compensation awarded to the subsidiaries				2.5
Compensation for expropriation of the investments of subsidiaries \| VENEZUELA \| Minimum
Commitments and Contingencies Disclosure [Line Items]
Compensation awarded to the subsidiaries				62

Fair_Value_Measurements_and_Di2

Fair Value Measurements and Disclosures - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
	Contract	Contract
Derivatives, Fair Value [Line Items]
Cash equivalents maturity period, days	90 days
Number of contracts outstanding	2	4
Notional value of foreign exchange contract	$2.30	$2.30

Schedule_of_Fair_Value_Other_F

Schedule of Fair Value Other Financial Instruments Measured (Detail) (USD $)	Mar. 31, 2015	Mar. 31, 2014
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	$3,007	$16,559
Money Market Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	3,007	16,559
Quoted Prices In Active Markets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	3,007	16,559
Quoted Prices In Active Markets (Level 1) \| Money Market Cash Equivalents
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of assets	$3,007	$16,559

Summary_of_Gain_on_Assets_Disp

Summary of Gain on Assets Disposition (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Fair Value Measurements [Line Items]
Amount of impairment incurred	$14,525	$9,341	$8,078
Combined fair value of assets incurring impairment	$28,509	$11,149	$14,733

Schedule_of_Gain_on_Dispositio

Schedule of Gain on Disposition of Assets (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	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, 2015	Mar. 31, 2014	Mar. 31, 2013
	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Vessel	Vessel	Vessel
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Gain on vessels disposed	$4,275	($1,537)	$3,590	$2,943	$2,363	$7,170	$49	$2,140	$9,271	$11,722	$6,609
Number of vessels disposed									13	48	32
Vessels
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Gain on vessels disposed									$2,988	$12,247	$12,191

Gain_on_Disposition_of_Assets_2

Gain on Disposition of Assets, Net - Additional Information (Detail) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Impaired Assets to be Disposed of by Method Other than Sale [Line Items]
Amortized gains on sale/leaseback transactions	$17.70
Reversal of accrued liability	3
Gain related to sale of asset		$4	$2.30

Segment_Information_Geographic2

Segment Information, Geographical Data and Major Customers - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2015
	Segment
Segment Reporting Information [Line Items]
Number of operating segments	4

Segment_Information_Geographic3

Segment Information, Geographical Data and Major Customers (Detail) (USD $)	3 Months Ended																12 Months Ended
In Thousands, unless otherwise specified	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, 2015		Mar. 31, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]
Vessel revenues																	$1,468,358		$1,418,461		$1,229,998
Other operating revenues																	27,159		16,642		14,167
Revenues	324,762		387,554		397,524		385,677		367,833		365,248		367,937		334,085		1,495,517		1,435,103		1,244,165
Operating profit																	285,934		296,878		251,718
General and administrative expenses																	-189,819		-187,976		-175,609
Corporate expenses																	-44,635		-50,776		-52,095
Gain on asset dispositions, net	4,275		-1,537		3,590		2,943		2,363		7,170		49		2,140		9,271		11,722		6,609
Goodwill impairment			-283,699								-56,283						-283,699	[1]	-56,283
Restructuring charge	-4,100																-4,052
Operating income (loss)	25,672	[2]	-213,580	[2]	84,723	[2]	66,004	[2]	61,063	[2]	20,488	[2]	76,565	[2]	43,425	[2]	-37,181		201,541		206,232
Foreign exchange gain																	8,678		1,541		3,011
Equity in net earnings of unconsolidated companies																	10,179		15,801		12,189
Interest income and other, net																	1,927		2,123		3,476
Loss on early extinguishment of debt																			-4,144
Interest and other debt costs																	-50,029		-43,814		-29,745
Earnings (loss) before income taxes																	-66,426		173,048		195,163
Depreciation and amortization																	175,204		167,480		147,299
Additions to properties and equipment																	366,563		806,484		452,582
Assets	4,756,162								4,885,829								4,756,162		4,885,829		4,168,055
Investments in and advances to unconsolidated companies	65,844								63,928								65,844		63,928		46,047
Americas
Segment Reporting Information [Line Items]
Goodwill impairment																	-114,237
Asia/Pacific
Segment Reporting Information [Line Items]
Goodwill impairment											-56,300								-56,283
Sub-Saharan Africa/Europe
Segment Reporting Information [Line Items]
Goodwill impairment																	-169,462
Operating Segments
Segment Reporting Information [Line Items]
Operating profit																	293,956		298,808		252,551
Depreciation and amortization																	167,217		164,112		143,895
Additions to properties and equipment																	223,581		599,410		273,524
Assets	4,253,391	[3]							4,435,925	[3]							4,253,391	[3]	4,435,925	[3]	3,701,393	[3]
Operating Segments \| Americas
Segment Reporting Information [Line Items]
Vessel revenues																	505,699		410,731		327,059
Operating profit																	122,988		90,936		40,318
Depreciation and amortization																	47,682		43,298		40,454
Additions to properties and equipment																	94,137		99,798		52,299
Assets	1,016,133	[3]							1,017,736	[3]							1,016,133	[3]	1,017,736	[3]	880,368	[3]
Operating Segments \| Asia/Pacific
Segment Reporting Information [Line Items]
Vessel revenues																	150,820		154,618		184,014
Operating profit																	11,541		29,044		43,704
Depreciation and amortization																	18,383		17,174		19,416
Additions to properties and equipment																	91,497		2,586		19,858
Assets	506,265	[3]							421,379	[3]							506,265	[3]	421,379	[3]	607,546	[3]
Operating Segments \| Middle East/North Africa
Segment Reporting Information [Line Items]
Vessel revenues																	205,787		186,524		149,412
Operating profit																	37,258		42,736		39,069
Depreciation and amortization																	27,538		24,441		18,784
Additions to properties and equipment																	1,842		8,042		3,833
Assets	666,983	[3]							613,303	[3]							666,983	[3]	613,303	[3]	507,124	[3]
Operating Segments \| Sub-Saharan Africa/Europe
Segment Reporting Information [Line Items]
Vessel revenues																	606,052		666,588		569,513
Operating profit																	122,169		136,092		129,460
Depreciation and amortization																	73,614		79,199		65,241
Additions to properties and equipment																	36,105	[4]	488,984	[4]	197,534	[4]
Assets	2,064,010	[3]							2,383,507	[3]							2,064,010	[3]	2,383,507	[3]	1,706,355	[3]
Other
Segment Reporting Information [Line Items]
Operating profit																	-8,022		-1,930		-833
Depreciation and amortization																	3,973		295		13
Additions to properties and equipment																	18,571		31,841
Assets	49,554								31,545								49,554		31,545		5,102
Corporate
Segment Reporting Information [Line Items]
General and administrative expenses																	-40,621	[5]	-47,703	[5]	-48,704	[5]
Depreciation and amortization																	4,014		3,073		3,391
Additions to properties and equipment																	124,411	[6]	175,233	[6]	179,058	[6]
Assets	387,373	[7]							354,431	[7]							387,373	[7]	354,431	[7]	415,513	[7]
Assets Before Equity Method Investments
Segment Reporting Information [Line Items]
Assets	4,302,945								4,467,470								4,302,945		4,467,470		3,706,495
Assets Before Corporate Assets
Segment Reporting Information [Line Items]
Assets	$4,368,789								$4,531,398								$4,368,789		$4,531,398		$3,752,542

[1]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
[2]	Operating income consists of revenues less operating costs and expenses, depreciation, vessel operating leases, goodwill impairment, general and administrative expenses and gain on asset dispositions, net, of the company's operations. Goodwill impairment by quarter for fiscal 2015 and 2014 and gain on asset dispositions, net, by quarter for fiscal 2015 and 2014, are as follows:
[3]	Marine support services are conducted worldwide with assets that are highly mobile. Revenues are principally derived from offshore service vessels, which regularly and routinely move from one operating area to another, often to and from offshore operating areas in different continents. Because of this asset mobility, revenues and long-lived assets attributable to the company's international marine operations in any one country are not material.
[4]	Included in Sub-Saharan Africa/Europe for the year ended March 31, 2014 is $245.6 million related to vessels acquired through the acquisition of Troms Offshore.
[5]	Included in Corporate general and administrative expenses for the year ended March 31, 2014 and 2013 are transaction costs of $3.7 million related to the acquisition of Troms Offshore and a settlement charge of $5.2 million related to the payment of retirement benefits to a former Chief Executive Officer, respectively.
[6]	Included in Corporate are additions to properties and equipment relating to vessels currently under construction which have not yet been assigned to a non-corporate reporting segment as of the dates presented.
[7]	Included in Corporate are vessels currently under construction which have not yet been assigned to a non-corporate reporting segment. The vessel construction costs will be reported in Corporate until the earlier of the vessels being assigned to a non-corporate reporting segment or the vessels' delivery. At March 31, 2015, 2014 and 2013, $235.2 million, $228.9 million and $229.3 million, respectively, of vessel construction costs are included in Corporate.

Segment_Information_Geographic4

Segment Information, Geographical Data and Major Customers (Parenthetical) (Detail) (USD $)	12 Months Ended						3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
General and administrative expenses	$189,819,000		$187,976,000		$175,609,000
Additions to properties and equipment	364,194,000		594,695,000		440,572,000
Corporate Vessels
Segment Reporting Information [Line Items]
Construction costs	235,200,000		228,900,000		229,300,000
Sub-Saharan Africa/Europe \| Troms Offshore Supply AS
Segment Reporting Information [Line Items]
Additions to properties and equipment			245,600,000
Chief Executive Officer
Segment Reporting Information [Line Items]
Settlement charge					5,200,000		-5,200,000
Corporate
Segment Reporting Information [Line Items]
General and administrative expenses	40,621,000	[1]	47,703,000	[1]	48,704,000	[1]
Corporate \| Troms Offshore Supply AS
Segment Reporting Information [Line Items]
General and administrative expenses			$3,700,000

[1]	Included in Corporate general and administrative expenses for the year ended March 31, 2014 and 2013 are transaction costs of $3.7 million related to the acquisition of Troms Offshore and a settlement charge of $5.2 million related to the payment of retirement benefits to a former Chief Executive Officer, respectively.

Schedule_of_Segment_Reporting_

Schedule of Segment Reporting Information, Revenue by Vessel Class (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	$1,468,358	$1,418,461	$1,229,998
Americas Fleet Deepwater vessels
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	353,232	263,750	179,032
Percentage of revenue	24.00%	18.00%	15.00%
Americas Fleet Towing-Supply/supply
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	125,029	115,055	120,817
Percentage of revenue	9.00%	8.00%	10.00%
Americas Fleet Other
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	27,438	31,926	27,210
Percentage of revenue	2.00%	3.00%	2.00%
Americas Fleet
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	505,699	410,731	327,059
Percentage of revenue	35.00%	29.00%	27.00%
Asia and Pacific Fleet Deepwater vessels
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	94,538	88,191	96,118
Percentage of revenue	6.00%	6.00%	8.00%
Asia/Pacific Fleet Towing-Supply/supply
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	53,281	62,630	84,217
Percentage of revenue	4.00%	5.00%	7.00%
Asia and Pacific Fleet Other
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	3,001	3,797	3,679
Asia and Pacific Fleet Other \| Maximum
Segment and Geographic Distribution of Operations [Line Items]
Percentage of revenue		1.00%	1.00%
Asia/Pacific Fleet
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	150,820	154,618	184,014
Percentage of revenue	10.00%	11.00%	15.00%
Middle East/North Africa Fleet Deepwater vessels
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	85,279	66,503	55,945
Percentage of revenue	6.00%	5.00%	5.00%
Middle East/North Africa Fleet Towing-Supply/supply
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	117,232	116,720	89,902
Percentage of revenue	8.00%	8.00%	7.00%
Middle East and North Africa Fleet Other
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	3,276	3,301	3,565
Middle East and North Africa Fleet Other \| Maximum
Segment and Geographic Distribution of Operations [Line Items]
Percentage of revenue		1.00%	1.00%
Middle East/North Africa fleet
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	205,787	186,524	149,412
Percentage of revenue	14.00%	13.00%	12.00%
Sub-Saharan Africa/Europe Fleet Deepwater vessels
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	326,315	364,722	273,544
Percentage of revenue	22.00%	26.00%	22.00%
Sub-Saharan Africa/Europe Fleet Towing-Supply/supply
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	208,324	231,224	226,357
Percentage of revenue	14.00%	16.00%	18.00%
Sub Saharan Africa And Europe Fleet Other
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	71,413	70,642	69,612
Percentage of revenue	5.00%	5.00%	6.00%
Sub-Saharan Africa/Europe Fleet
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	606,052	666,588	569,513
Percentage of revenue	41.00%	47.00%	46.00%
Worldwide Fleet Deepwater vessels
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	859,364	783,166	604,639
Percentage of revenue	58.00%	55.00%	50.00%
Worldwide Fleet Towing-Supply/supply
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	503,866	525,629	521,293
Percentage of revenue	35.00%	37.00%	42.00%
Worldwide Fleet Other
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	105,128	109,666	104,066
Percentage of revenue	7.00%	8.00%	8.00%
Worldwide Fleet
Segment and Geographic Distribution of Operations [Line Items]
Vessel revenues	$1,468,358	$1,418,461	$1,229,998
Percentage of revenue	100.00%	100.00%	100.00%

Disclosure_of_Accounted_Total_

Disclosure of Accounted Total Revenues Percentage (Detail) (Customer Concentration Risk, Sales Revenue, Net)	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2013
Chevron Corporation
Revenue, Major Customer [Line Items]
Total revenue percentage	12.70%	18.10%	17.80%
Petroleo Brasileiro Sa
Revenue, Major Customer [Line Items]
Total revenue percentage	11.80%	8.60%	8.60%
Bp Plc
Revenue, Major Customer [Line Items]
Total revenue percentage	10.10%	8.90%	7.90%

Goodwill_Additional_Informatio

Goodwill - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended				3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2015		Mar. 31, 2014		Jun. 30, 2014
Goodwill [Line Items]
Goodwill impairment charge	$283,699	$56,283	$283,699	[1]	$56,283
Goodwill					42,160	[2]
Asia/Pacific
Goodwill [Line Items]
Goodwill impairment charge		56,300			56,283
Goodwill impairment test period		10 years
Sub-Saharan Africa/Europe
Goodwill [Line Items]
Goodwill impairment charge			169,462
Goodwill					$42,160		$42,200

[1]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.
[2]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.

Schedule_of_Goodwill_and_Chang

Schedule of Goodwill and Changes to Goodwill by Reportable Segment (Detail) (USD $)	3 Months Ended		12 Months Ended				3 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2015		Mar. 31, 2014		Jun. 30, 2014		Mar. 31, 2013
Goodwill [Line Items]
Goodwill, Beginning Balance			$283,699	[1],[2]	$297,822	[1]	$283,699	[1],[2]
Goodwill acquired					42,160	[1]
Impairments	283,699	56,283	283,699	[2]	56,283
Goodwill, Ending Balance					283,699	[1],[2]
Asia/Pacific
Goodwill [Line Items]
Goodwill, Beginning Balance					56,283
Impairments		56,300			56,283
Americas
Goodwill [Line Items]
Goodwill, Beginning Balance			114,237				114,237		114,237
Impairments			114,237
Goodwill, Ending Balance									114,237
Sub-Saharan Africa/Europe
Goodwill [Line Items]
Goodwill, Beginning Balance			169,462		127,302		169,462
Goodwill acquired					42,160		42,200
Impairments			169,462
Goodwill, Ending Balance					$169,462

[1]	The total carrying amount of goodwill at December 31, 2013 is net of accumulated impairment charges $30.9 million and $56.3 million related to the Middle East/North Africa and Asia/Pacific segments, respectively.
[2]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.

Schedule_of_Goodwill_and_Chang1

Schedule of Goodwill and Changes to Goodwill by Reportable Segment (Parenthetical) (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Goodwill [Line Items]
Accumulated impairment charges	$370.90
Middle East/North Africa
Goodwill [Line Items]
Accumulated impairment charges		30.9
Asia/Pacific
Goodwill [Line Items]
Accumulated impairment charges		$56.30

Summary_of_Goodwill_as_a_Perce

Summary of Goodwill as a Percentage of Total Assets and Stockholders' Equity (Detail)	Mar. 31, 2014
Goodwill [Line Items]
Goodwill as a percentage of total assets	6.00%
Goodwill as a percentage of stockholders' equity	11.00%

Restructuring_Charge_Additiona

Restructuring Charge - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring charge	$4,100	$4,052

Selected_Financial_Information

Selected Financial Information (Detail) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	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, 2015	Mar. 31, 2014	Mar. 31, 2013
Quarterly Financial Data [Line Items]
Revenues	$324,762		$387,554		$397,524		$385,677		$367,833		$365,248		$367,937		$334,085		$1,495,517	$1,435,103	$1,244,165
Operating income (loss)	25,672	[1]	-213,580	[1]	84,723	[1]	66,004	[1]	61,063	[1]	20,488	[1]	76,565	[1]	43,425	[1]	-37,181	201,541	206,232
Net earnings attributable to Tidewater Inc.	($9,076)		($160,694)		$60,907		$43,673		$43,417		$12,583		$54,172		$30,083		($65,190)	$140,255	$150,750
Basic earnings per share attributable to Tidewater Inc.	($0.19)		($3.31)		$1.23		$0.88		$0.88		$0.25		$1.10		$0.61		($1.34)	$2.84	$3.04
Diluted earnings per share attributable to Tidewater Inc.	($0.19)		($3.31)		$1.22		$0.88		$0.88		$0.25		$1.09		$0.61		($1.34)	$2.82	$3.03

[1]	Operating income consists of revenues less operating costs and expenses, depreciation, vessel operating leases, goodwill impairment, general and administrative expenses and gain on asset dispositions, net, of the company's operations. Goodwill impairment by quarter for fiscal 2015 and 2014 and gain on asset dispositions, net, by quarter for fiscal 2015 and 2014, are as follows:

Selected_Financial_Information1

Selected Financial Information (Parenthetical) (Detail) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	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, 2015		Mar. 31, 2014	Mar. 31, 2013
Quarterly Financial Data [Line Items]
Goodwill impairment		($283,699)				($56,283)			($283,699)	[1]	($56,283)
Gain on asset dispositions, net	$4,275	($1,537)	$3,590	$2,943	$2,363	$7,170	$49	$2,140	$9,271		$11,722	$6,609

[1]	The total carrying amount of goodwill at December 31, 2014 is net of accumulated impairment charges of $370.9 million.

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	1 Months Ended	12 Months Ended	1 Months Ended			2 Months Ended	1 Months Ended	0 Months Ended
	Mar. 31, 2015	Mar. 31, 2015	Apr. 30, 2015	27-May-15	31-May-15	27-May-15	Apr. 23, 2015	27-May-15
	Mar. 31, 2015	Mar. 31, 2015	Contract	27-May-15	Vessel	Vessel	Vessel	27-May-15
Subsequent Event [Line Items]
Amount remaining authorized to repurchase shares	$100,000,000	$100,000,000
Number of Vessels, commitments	21	21
Troms Offshore Supply AS \| Notes Due April 2027
Subsequent Event [Line Items]
Debt instruments face amount	29,500,000	29,500,000
Debt instrument maturity, month and year	2027-01
Semi-annual principal payments	1,200,000
Debt instrument bearing floating interest rate	2.91%	2.91%
Indebtedness rate	1.30%
Total capitalization rate	4.21%	4.21%
Deepwater PSVs
Subsequent Event [Line Items]
Aggregate installment payment	1,000,000	1,000,000
7145 BHP towing-supply-class ATHS vessels
Subsequent Event [Line Items]
Aggregate installment payment	1,000,000	1,000,000
Current Credit Facility
Subsequent Event [Line Items]
Credit facility expiration date		2018-06
Revolving credit facility	900,000,000	900,000,000
Credit facility term		5 years
Revolving line of credit		600,000,000
Term loan		300,000,000
Subsequent Event
Subsequent Event [Line Items]
Number of terminated contracts			3
Subsequent Event \| Troms Offshore Supply AS \| Notes Due April 2027
Subsequent Event [Line Items]
Debt instruments face amount				31,300,000		31,300,000		31,300,000
Debt instrument maturity, month and year				2027-04
Semi-annual principal payments				1,300,000
Debt instrument bearing floating interest rate				2.92%		2.92%		2.92%
Indebtedness rate				1.30%
Total capitalization rate				4.22%		4.22%		4.22%
Subsequent Event \| Deepwater PSVs
Subsequent Event [Line Items]
Aggregate installment payment				5,400,000	5,700,000	5,400,000		5,400,000
Aggregate estimated remaining cost					41,000,000
Number of vessels under construction					2	2
Significant commitment, new construction delivery date				30-Jun-16	30-Jun-16
Obligation to be relieved						21,700,000
Subsequent Event \| 7145 BHP towing-supply-class ATHS vessels
Subsequent Event [Line Items]
Number of Vessels, commitments							6
Number of terminated contracts							3
Aggregate installment payment							36,100,000
Aggregate estimated remaining cost							12,700,000
Subsequent Event \| Current Credit Facility
Subsequent Event [Line Items]
Credit facility expiration date								2019-06
Revolving credit facility				900,000,000		900,000,000		900,000,000
Credit facility term								5 years
Revolving line of credit								600,000,000
Term loan								$300,000,000

Valuation_and_Qualifying_Accou1

Valuation and Qualifying Accounts (Detail) (Allowance for Doubtful Accounts, USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014		Mar. 31, 2013
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$35,737	$46,332		$49,921
Additions at Cost	2,405	1,399		900
Deductions	508	11,994	[1]	4,489	[2]
Balance at End of Period	$37,634	$35,737		$46,332

[1]	Of this amount, $3,151 represents the collections from one customer located in Mexico and $8,843 represents accounts receivable amounts considered uncollectible and removed from accounts receivable with an offsetting reduction to the allowance for doubtful accounts.
[2]	Of this amount, $3,852 is related to the revaluation of the allowance for doubtful accounts related to Venezuelan receivables and $637 related to receivables considered uncollectible and removed from accounts receivable by reducing the allowance for doubtful accounts.

Valuation_and_Qualifying_Accou2

Valuation and Qualifying Accounts (Parenthetical) (Detail) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2013	Mar. 31, 2014
Venezuela Customer
Valuation and Qualifying Accounts Disclosure [Line Items]
Amount uncollectible and removed from account receivable	$637
Revaluation allowance for doubtful accounts	3,852
Mexico Customer
Valuation and Qualifying Accounts Disclosure [Line Items]
Collections from accounts receivable		3,151
Amount uncollectible and removed from account receivable		$8,843