Saving and Retirement Plans - 401(K) Plan (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Amount	$ 5,000
Defined Contribution Plan, Cost Recognized	$ 1,400,000	$ 1,200,000	$ 1,100,000