Summary of Significant Accounting Policies (Intangible Assets - Useful Life) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets
Amortization expense recognized	$ 5,000,000	$ 4,500,000	$ 2,300,000
Amortization expense expected to be incurred, 2014	5,000,000
Amortization expense expected to be incurred, 2015	5,000
Amortization expense expected to be incurred, 2016	5,000
Amortization expense expected to be incurred, 2017	5,000
Amortization expense expected to be incurred, 2018	4,900,000
Amortization expense expected to be incurred, after year five	$ 32,400,000
Minimum
Finite-Lived Intangible Assets
Estimated useful lives (in years)	5 years
Maximum
Finite-Lived Intangible Assets
Estimated useful lives (in years)	20 years