Stock-Based Compensation 2 (Details) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Third Amended 2003 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding	3,594,246	3,596,871	3,014,220	2,311,111
Granted	75,271	684,635	752,433
Exercised	(77,386)	(91,044)	(14,889)
Forfeited	(510)	(10,940)	(34,435)
Weighted-average exercise price - Outstanding	$ 21.75	$ 21.51	$ 20.69	$ 20.61
Weighted-average exercise price - Granted	$ 28.49	$ 24.90	$ 20.72
Weighted-average exercise price - Exercised	$ 17.22	$ 19.48	$ 16.83
Weighted-average exercise price - Forfeited	$ 24.06	$ 25.60	$ 17.39
Exercisable	2,478,000	1,814,539	1,229,447
Weighted-average exercise price - Exercisable	$ 19.86	$ 19.83	$ 20.70
Long Term Stock Incentive 1992 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding	0	39,159	49,019	312,109
Granted	0	0	0
Exercised	(29,188)	(9,860)	(263,090)
Forfeited	(9,971)	0	0
Weighted-average exercise price - Outstanding	$ 0	$ 14.65	$ 14.65	$ 13.70
Weighted-average exercise price - Granted	$ 0	$ 0	$ 0
Weighted-average exercise price - Exercised	$ 14.65	$ 14.65	$ 13.52
Weighted-average exercise price - Forfeited	$ 14.65	$ 0	$ 0
Exercisable	0	39,159	49,019
Weighted-average exercise price - Exercisable	$ 0	$ 14.65	$ 14.65

Number of share options granted during the current period.

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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 Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(c), d(2)

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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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-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

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- Definition

The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

+ References

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-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

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- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(f)

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- Definition

The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

+ References

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

-Publisher FASB

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-Number 123R

-Paragraph A240

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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 stock options awarded under the plan during the reporting period.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(1)(d)

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- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance sheet date, including vested options.

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The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Number of share options (or share units) exercised during the current period.

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