Cumulative Other Comprehensive Income (Loss) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expenses	$ 37,935	$ 51,896
Equity in earnings of investees	(10,934)	(4,262)
Total reclassifications	(1,222)
Cumulative Other Comprehensive Income (Loss) to Net Income
Reclassifications out of cumulative other comprehensive income (Loss)
Total reclassifications	1,222
Unrealized gains and losses on available for sale securities
Reclassifications out of cumulative other comprehensive income (Loss)
Total reclassifications	7
Unrealized gains and losses on available for sale securities | Cumulative Other Comprehensive Income (Loss) to Net Income
Reclassifications out of cumulative other comprehensive income (Loss)
Equity in earnings of investees	(7)
Interest rate swap contracts | Cumulative Other Comprehensive Income (Loss) to Net Income
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expenses	$ 1,229