Stock Compensation Stock Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	3,526,936
Share-based Compensation Arrangements, Stock Dividend Equivalents, Net of Taxes	$ 2,580	$ 2,480	$ 4,342
Granted, Weighted Average Exercise Price	$ 16.36	$ 14.89	$ 12.76
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	2,051	673	22,771
Tax benefit of options exercised	821	269	9,162
Exercise of employee stock options, net of shares to pay exercise price, shares	506,020	122,085	4,834,360
Exercised, Weighted Average Exercise Price	$ 11.39	$ 10.36	$ 9.09
Exercise of employee stock options, net of shares to pay exercie price	1,029	1,265	1,144
Share Based Compensation, Options, Number Of Shares Used To Pay Exercise Price, Adjusted for Stock Dividend	315,839		3,103,389
Share-based Compensation, Options, Shares Exercised Fair Value	4,777		42,768
Share-based Compensation, Options, Shares Exercised Fair Value Per Share	$ 15.12		$ 13.25
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Allocated Share-based Compensation Expense	1,715	1,218	292
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 3,860	$ 4,057
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition (in years)	2.43	3.04
Non-Qualfied Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period	479,850	110,250	1,234,800
Granted, Weighted Average Exercise Price		$ 14.89	$ 12.76
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised, Weighted Average Exercise Price	$ 10.97	$ 8.32	$ 8.60
Minimum [Member] | Non-Qualfied Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Exercise Price	$ 15.13
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised, Weighted Average Exercise Price	$ 13.24	$ 12.48	$ 12.84
Maximum [Member] | Non-Qualfied Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted, Weighted Average Exercise Price	$ 16.43