Shareholders' Equity and Stock-Based Compensation Plans Compensation Expense and Related Tax Benefits (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended						1 Months Ended	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Stock Options And Restricted Stock [Member]	Dec. 31, 2010 Stock Options And Restricted Stock [Member]	Dec. 31, 2009 Stock Options And Restricted Stock [Member]	Jan. 31, 2009 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2011 Non Qualified Stock Options [Member]	Dec. 31, 2009 Non Qualified Stock Options [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2009 Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense	$ 4,249	$ 1,996	$ 1,781	$ 4,249	$ 1,996	$ 1,781						$ 3,194	$ 1,172	$ 458
Tax benefit				(1,192)	(456)	(241)						(1,119)	(412)	(164)
Stock-based compensation expense, net of tax				$ 3,057	$ 1,540	$ 1,540						$ 2,075	$ 760	$ 294
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate	35.00%	35.00%	35.00%
Granted, Stock Options							485,000	616,686	578,000	1,000	42,000