Employee Benefit Plans and Shareholder Rights Plan - Stock Option Activity (Details) (USD $)	12 Months Ended
	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance, beginning of year, Shares Under Option	82,000
Balance, beginning of year, Weighted Average Exercise Price	$ 8.44
Granted, Shares Under Option	0
Granted, Weighted Average Exercise Price	$ 0.00
Exercised, Shares Under Option	(82,000)
Exercised, Weighted Average Exercise Price	$ 8.44
Exercises in Period, Aggregate Intrinsic Value	$ 1,858,000
Forfeited, Shares Under Option	0
Forfeited, Weighted Average Exercise Price	$ 0.00
Balance, end of year, Shares Under Option	0
Balance, end of year, Weighted Average Exercise Price	$ 0.00
Employee Service Share-based Compensation, Cash Received from Exercise of Stock Options	700,000
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 900,000