Debt - Long Term Debt (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016	Dec. 27, 2015
Debt Instrument [Line Items]
Unamortized Debt Issuance Expense	$ (4,891)	$ (6,279)
Debt and Capital Lease Obligations	592,500	612,500
Long-term Debt and Capital Lease Obligations, Current	0	0
Long-term Debt and Capital Lease Obligations	587,609	606,221
Senior Unsecured 5.00% Due 2028
Debt Instrument [Line Items]
Long-term debt	300,000	300,000	$ 300,000
Unamortized Debt Issuance Expense	(3,746)	(4,370)
Incremental Commitment Agreement [Member] \| Secured Debt [Member] \| 2011 Credit Facility Due 2018
Debt Instrument [Line Items]
Line of Credit Facility, Incremental Term Loan Commitment	292,500	312,500
Unamortized Debt Issuance Expense	$ (1,145)	$ (1,909)

Line of Credit Facility, Incremental Term Loan Commitment

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- Definition

Sum of the carrying values as of the balance sheet date of all debt, including all short-term borrowings, long-term debt, and capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13,16)
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+ References

No definition available.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Publisher FASB
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- Definition

Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Amount of long-term debt and capital leases due within one year or the normal operating cycle, if longer.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
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- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
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