Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		$ 3,062,923
Ending Balance		3,054,916
Total accumulated other comprehensive loss		3,062,923		$ 3,054,916	$ 3,062,923
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				2,995,841	3,003,391
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		(56,767)	$ (17,256)
Unrealized loss		3,177	(5,087)
Ending Balance		(53,590)	(22,343)
Total accumulated other comprehensive loss		(56,767)	(17,256)	(53,590)	(56,767)	$ (22,343)
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		(455)	(865)
Unrealized loss		127	(1,643)
Reclassification adjustment	[1]	186	283
Ending Balance		(142)	(2,225)
Total accumulated other comprehensive loss		(455)	(865)	(142)	(455)	(2,225)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		(53,732)	(24,568)
Total accumulated other comprehensive loss		(53,732)	(24,568)	(53,732)		(24,568)
AOCI Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		1,110	380
Total accumulated other comprehensive loss		1,110	$ 380	1,110		380
AOCI Attributable to Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		(56,031)
Ending Balance		(52,622)
Total accumulated other comprehensive loss		$ (56,031)		(52,622)	$ (56,031)
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				$ (52,622)		$ (24,188)

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