Share-Based Compensation (Details 3) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Summary of stock option activity
Options outstanding, Beginning Balance, Shares	584,201	763,794	541,718
Options outstanding, Beginning Balance, Weighted Average Exercise Price	$ 23.32	$ 23.38	$ 25.74
Options outstanding, Beginning Balance, Options Exercisable	396,688	451,194	462,683
Granted, Shares	0		280,900
Granted, Weighted Average Exercise Price			$ 19.20
Exercised, Shares	(12,099)	(14,616)	(22,311)
Exercised, Weighted Average Exercise Price	$ 19.41	$ 20.14	$ 23.21
Shares Forfeited or Expired	(208,206)	(164,977)	(36,513)
Weighted Average Exercise Price Forfeited	$ 25.81	$ 23.88	$ 26.34
Options outstanding, Ending Balance, Shares	363,896	584,201	763,794
Options outstanding, Ending Balance, Weighted Average Exercise Price	$ 22.03	$ 23.32	$ 23.38
Options outstanding, Ending Balance, Options Exercisable	276,009	396,688	451,194

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.

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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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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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