Stock Incentive Plans (Details 2) (Stock option plans, USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock option plans
Shares
Outstanding at beginning of year (in shares)	1,017,922	1,351,593	1,592,755
Granted (in shares)			67,500
Forfeited (in shares)	(160,454)	(333,671)	(308,662)
Outstanding at end of year (in shares)	857,468	1,017,922	1,351,593
Exercisable at end of year (in shares)	857,468	1,017,922	1,291,593
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share)	$ 16.23	$ 16.09	$ 16.12
Granted (in dollars per share)			$ 4.49
Forfeited (in dollars per share)	$ 12.07	$ 15.67	$ 13.70
Outstanding at end of year (in dollars per share)	$ 17.01	$ 16.23	$ 16.09
Exercisable at end of year (in dollars per share)	$ 17.01	$ 16.23	$ 16.63
Weighted-average fair value per option for options granted during the year (in dollars per share)			$ 1.48

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 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.

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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.

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

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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