Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

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-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

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-Section F

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- Definition

As of the balance sheet date, the aggregate unrecognized cost of equity-based awards made to employees under equity-based compensation awards that have yet to vest.

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Publisher FASB

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-Glossary Financing Activities

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-Publisher FASB

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-Number 95

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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-Number 95

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- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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- Definition

The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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- Definition

Gross number of share options (or share units) granted during the period.

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No definition available.

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Equity Compensation Plans - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense	$ 0.4	$ 0.4	$ 0.8	$ 0.8
Cash received from exercise of stock option	0.2		0.2
Number of options exercised, intrinsic value	0.1		0.1
Number of options granted		0		0
Restricted shares granted				22,120
Stock Option Plan 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share options and restricted shares authorized	1,750,000		1,750,000
Additional shares authorized under the plan			1,200,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	1.1		1.1
Weighted average expected amortization period	2 years 9 months 18 days		2 years 9 months 18 days
Performance Based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted shares granted	114,500		114,500
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost	$ 2.1		$ 2.1
Weighted average expected amortization period	2 years 2 months 12 days		2 years 2 months 12 days
Unvested restricted stock awards	369,776		369,776