Description of Business and Summary of Significant Accounting Policies (Employee Savings Plans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Matching contribution, 401(k) plan	$ 3,500,000	$ 2,100,000	$ 0
Deferred Compensation Arrangement With Individual Matching Contribution Annual Vesting Years Two and Three	33.00%
Balances due to participants	40,600,000	34,100,000
Employer matching contribution [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Matching contributions to employee participants	$ 500,000	$ 600,000	$ 0
Deferred Compensation Arrangement With Individual Matching Contribution Annual Vesting Portion, Year One	33.00%
Employer discretionary contribution [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Employer contributions vesting periods (in years)	3 years
Employees Hired Subsequent to January 1, 2011 [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Defined Contribution Plan Matching Contribution Requisite Service Period	3 years