Fair Value Measurement - Additional Information (Detail) - USD ($) $ in Thousands	Apr. 30, 2016	Jan. 31, 2016
Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable (Note 6)	$ 242,037	$ 240,076
Business Combination, Contingent Consideration, Liability, Current	1,042	1,460
Business Combination, Contingent Consideration, Liability, Noncurrent	1,299	2,289
Contingent consideration	2,341	3,749
Current portion of notes payable	0	0
4.00% Debentures due 2031
Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis
Fair value of notes payable	267,032	255,487
Notes payable (Note 6)	236,849	234,888
Notes Payable, Other Payables
Fair Value, Liabilities Measured on Recurring and Nonrecurring Basis
Notes payable (Note 6)	$ 5,188	$ 5,188

Amount of liability recognized arising from contingent consideration in a business combination.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
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-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled within one year or the normal operating cycle, if longer.

+ References

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Amount of liability recognized arising from contingent consideration in a business combination, expected to be settled beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Carrying value as of the balance sheet date of notes payable (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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Sum of the carrying values as of the balance sheet date of the portions of all long-term notes and loans payable due within one year or the operating cycle if longer.

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Fair value portion of notes payable.

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