Supplemental Cash Flow Information - Details of Supplemental Cash Flow Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Cash paid during the period for:
Income taxes, net	$ 79us-gaap_IncomeTaxesPaidNet	$ 4,242us-gaap_IncomeTaxesPaidNet
Interest, net	417us-gaap_InterestPaidNet	287us-gaap_InterestPaidNet
Non-Cash Transaction Information:
Employee stock purchase plan	152	164
Equipment acquired under capital leases	$ 249us-gaap_CapitalLeaseObligationsIncurred	$ 72us-gaap_CapitalLeaseObligationsIncurred

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The increase during the period in capital lease obligations due to entering into new capital leases.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4313-108586

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-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 3

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- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

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The amount of cash paid for interest during the period net of cash paid for interest that is capitalized.

+ References

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- Definition

Aggregate change in value for stock issued during the period as a result of employee stock purchase plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

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-Name Accounting Standards Codification

-Topic 505

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-Section S99

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-Subparagraph (SX 210.3-04)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30, 31

-Article 5

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