Represents the amount of equity grant forfeitures during the period.

No definition available.

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- Definition

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.

+ References

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

-Publisher FASB

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-Publisher SEC

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- Definition

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

+ References

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

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-Name Accounting Standards Codification

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- Definition

Unrecognized cost of unvested share-based compensation awards.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

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Unrecognized Compensation Cost (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost at beginning of period	$ 20,730
Equity grants	9,652
Equity grant forfeitures	(363)
Equity compensation expense	(9,750)	(10,077)	(9,784)
Unrecognized Compensation Cost at End of Period	20,269	20,730
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized Compensation Cost at End of Period	1,000
Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation expense	(6,000)	(6,000)	(7,000)
Unrecognized Compensation Cost at End of Period	12,000
Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity compensation expense	(3,000)	(3,000)	(2,000)
Unrecognized Compensation Cost at End of Period	7,000
Incentive Plans \| Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost at beginning of period	1,869
Equity grants	107
Equity grant forfeitures	(213)
Equity compensation expense	(672)
Unrecognized Compensation Cost at End of Period	1,091
Incentive Plans \| Deferred Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost at beginning of period	13,044
Equity grants	5,305
Equity grant forfeitures	(150)
Equity compensation expense	(5,895)
Unrecognized Compensation Cost at End of Period	12,304
Incentive Plans \| Performance Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost at beginning of period	5,817
Equity grants	4,025
Equity compensation expense	(2,968)
Unrecognized Compensation Cost at End of Period	6,874
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity grants	215
Equity compensation expense	$ (215)