Summary of Stock Options Summarized by Exercise Price (Detail) (USD $)	3 Months Ended
Mar. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised, Lower Range	$ 7.50
Outstanding Weighted Average, Exercise Price	$ 7.80	$ 7.76
Exercisable Weighted Average, Exercise Price	$ 7.74	$ 7.70
Incentive Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Weighted Average, Shares	478,379
Outstanding Weighted Average, Remaining Life (Months)	80 months
Outstanding Weighted Average, Exercise Price	$ 7.80
Exercisable Weighted Average, Shares	471,712
Exercisable Weighted Average, Exercise Price	$ 7.74
Incentive Stock Option Plan \| Range One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised, Lower Range	$ 7.50
Outstanding Weighted Average, Shares	451,700
Outstanding Weighted Average, Remaining Life (Months)	80 months
Outstanding Weighted Average, Exercise Price	$ 7.50
Exercisable Weighted Average, Shares	451,700
Exercisable Weighted Average, Exercise Price	$ 7.50
Incentive Stock Option Plan \| Range Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options exercised, Lower Range	$ 11.32
Options exercised, Upper Range	$ 14.75
Outstanding Weighted Average, Shares	26,679
Outstanding Weighted Average, Remaining Life (Months)	77 months
Outstanding Weighted Average, Exercise Price	$ 12.90
Exercisable Weighted Average, Shares	20,012
Exercisable Weighted Average, Exercise Price	$ 13.10

Share based compensation by share based payment award option outstanding weighted average number of shares.

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- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(i)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (e)(1)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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