Stock Option Plans and Share-Based Compensation Restricted Stock Awards and RSUs rollforward (Details) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Restricted Stock [Member]
Number of shares [Roll Forward]
Beginning balance	68	77	52
Granted	67	68	79
Vested	(78)	(77)	(54)
Ending balance	58	68	77
Weighted-average grant date fair value per share [Roll Forward]
Beginning balance	$ 14.71	$ 12.91	$ 9.25
Granted	$ 14.19	$ 14.71	$ 12.91
Vested	$ 14.64	$ 12.91	$ 9.40
Ending balance	$ 14.19	$ 14.71	$ 12.91
Vested in period, fair value	$ 1,100,000.00	$ 1,100,000.00	$ 700,000.00
Compensation cost not yet recognized	300,000.00
Period for recognition	5 months
Restricted Stock Units (RSUs) [Member]
Number of shares [Roll Forward]
Beginning balance	287	308	264
Granted	274	145	195
Vested	(153)	(152)	(140)
Forfeited	(19)	(14)	(11)
Ending balance	389	287	308
Weighted-average grant date fair value per share [Roll Forward]
Beginning balance	$ 13.03	$ 12.98	$ 14.32
Granted	$ 14.58	$ 14.39	$ 12.83
Vested	$ 12.90	$ 14.26	$ 15.10
Forfeited	$ 14.55	$ 12.82	$ 15.34
Ending balance	$ 14.09	$ 13.03	$ 12.98
Vested in period, fair value	2,300,000.00	2,400,000.00	1,900,000.00
Compensation cost not yet recognized	$ 5,100,000.00
Period for recognition	2 years 2 months 12 days

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

Aggregate unrecognized cost of share-based awards, other than options, made to employees under an equity-based compensation plan, that have yet to vest.

+ References

No definition available.

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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 weighted average fair value at grant date for nonvested equity-based awards issued 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).

+ References

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

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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.

+ References

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

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- Definition

The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

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- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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- Definition

The total fair value of equity-based awards for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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- Definition

The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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