Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		$ 3,009,947
Ending Balance		2,932,447
Total accumulated other comprehensive loss		3,009,947		$ 2,932,447	$ 3,009,947
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				2,876,817	2,952,928
Accumulated Foreign Currency Adjustment Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		(17,256)	$ (5,823)
Unrealized loss		(18,596)	1,741
Ending Balance		(35,852)	(4,082)
Total accumulated other comprehensive loss		(17,256)	(5,823)	(35,852)	(17,256)	$ (4,082)
Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		(865)	(377)
Unrealized loss		(2,354)	(1,022)
Reclassification adjustment	[1]	559	703
Ending Balance		(2,660)	(696)
Total accumulated other comprehensive loss		(865)	(377)	(2,660)	(865)	(696)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		(38,512)	(4,778)
Total accumulated other comprehensive loss		(38,512)	(4,778)	(38,512)		(4,778)
AOCI Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		709	(85)
Total accumulated other comprehensive loss		709	$ (85)	709		(85)
AOCI Attributable to Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		(17,893)
Ending Balance		(37,803)
Total accumulated other comprehensive loss		$ (17,893)		(37,803)	$ (17,893)
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				$ (37,803)		$ (4,863)

[1] Amounts reclassified out of Accumulated Other Comprehensive Loss/General & Limited Partner's Equity into contractual interest expense.