Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		$ 3,062,923
Ending Balance		3,060,660
Total accumulated other comprehensive loss		3,062,923		$ 3,060,660	$ 3,062,923
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				3,001,589	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)	$ (22,023)
Unrealized income (loss)		10,680	(18,596)
Ending Balance		(46,087)	(40,619)
Total accumulated other comprehensive loss		(56,767)	(22,023)	(46,087)	(56,767)	$ (40,619)
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 income (loss)		(41)	(2,354)
Reclassification adjustment	[1]	316	559
Ending Balance		(180)	(2,660)
Total accumulated other comprehensive loss		(455)	(865)	(180)	(455)	(2,660)
AOCI Including Portion Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		(46,267)	(43,279)
Total accumulated other comprehensive loss		(46,267)	(43,279)	(46,267)		(43,279)
AOCI Attributable to Noncontrolling Interest [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Ending Balance		935	863
Total accumulated other comprehensive loss		935	$ 863	935		863
AOCI Attributable to Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance		(56,031)
Ending Balance		(45,332)
Total accumulated other comprehensive loss		$ (56,031)		(45,332)	$ (56,031)
Total accumulated other comprehensive loss included in shareholders' equity/owners' equity				$ (45,332)		$ (42,416)

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