Stock Based Compensation Restricted and Unrestricted Shares with Market Conditions (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	12 Months Ended
	Feb. 28, 2011	Dec. 31, 2011
Relative TSR [Member] | Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	$ 1,066
Unamortized Value Of Restricted and Unrestricted Shares		742
Relative TSR [Member] | Unrestricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	1,066
Unamortized Value Of Restricted and Unrestricted Shares		826
Absolute TSR [Member] | Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	365
Unamortized Value Of Restricted and Unrestricted Shares		254
Absolute TSR [Member] | Unrestricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted and Unrestricted Share Awards, Grant Date Fair Value	365
Unamortized Value Of Restricted and Unrestricted Shares		$ 283