Benefit Plans Share Option Activity (Details) (Share Options [Member], USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Shares Outstanding, Beginning of Period	3,888,281	4,389,605	2,252,000
Weighted-Average Exercise Price Per Share Oustanding, Beginning of Period	$ 6.36	$ 6.23	$ 4.97
Number of Shares Granted			2,514,001
Weighed-Average Exercise Price Per Share Granted			$ 7.16
Number of Shares Exercised	(408,201)	(501,324)	(352,628)
Weighed-Average Exercise Price Per Share Exercised	$ 5.73	$ 5.16	$ 4.97
Number of Shares Forfeited			(23,768)
Weighed-Average Exercise Price Per Share Forfeited			$ 5.18
Number of Shares Outstanding, End of Period	3,480,080	3,888,281	4,389,605
Weighted-Average Exercise Price Per Share Oustanding, End of Period	$ 6.44	$ 6.36	$ 6.23

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

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)(e)

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For presentations that combine terminations, 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 or that expired.

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The combined weighted average exercise price associated with stock options during the period that have either lapsed or been forfeited.

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

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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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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