Incentive Plan (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares granted per employee	1,500,000
Maximum amount of cash paid per employee	$ 10.0
Number of shares remaining for issuance under the "Incentive Plan"	3,488,165
2004 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized and reserved for issuance under the "Incentive Plan"	4,474,102
Amended And Restated 2004 Incentive Award Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized and reserved for issuance under the "Incentive Plan"	9,474,102
Increase in number of shares reserved for issuance	5,000,000