Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified					3 Months Ended		9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Dec. 31, 2012	Jun. 30, 2014 Recurring Available-for-sale Securities	Jun. 30, 2013 Recurring Available-for-sale Securities	Sep. 30, 2014 Recurring Available-for-sale Securities	Sep. 30, 2013 Recurring Available-for-sale Securities	Sep. 30, 2014 Fair Value, Inputs, Level 1 [Member] Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Restricted Cash and Cash Equivalents	$ 114,392	$ 122,773							$ 114,392
Cash and Cash Equivalents, at Carrying Value	474,338	654,613	238,150	618,217
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period							0	40,388
Total gains/(losses), net:
Included in other revenue					0	0	0	1,613
Settlements					0	0	0	(42,001)
Balance at end of period					$ 0	$ 0	$ 0	$ 0