Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other comprehensive (loss) income:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 1,151	$ (10,332)	$ (10,089)
Parent Company [Member]
Net income	178,980	166,992	152,543
Other comprehensive (loss) income:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	1,151	(10,332)	(10,089)
Reclassification adjustment of derivative instruments included in net income	11,103	51,139	9,152
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	(8)	24	(43)
Other comprehensive income (loss)	12,246	40,831	(980)
Comprehensive income	191,226	207,823	151,563
Less: comprehensive income (loss) attributable to noncontrolling interests:
Net income attributable to noncontrolling interests	2,903	2,070	2,487
Comprehensive income attributable to noncontrolling interests	3,092	2,554	2,452
Comprehensive income attributable to the Company	188,134	205,269	149,111
Partnership Interest [Member]
Net income	178,980	166,992	152,543
Other comprehensive (loss) income:
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	1,151	(10,332)	(10,089)
Reclassification adjustment of derivative instruments included in net income	11,103	51,139	9,152
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	(8)	24	(43)
Other comprehensive income (loss)	12,246	40,831	(980)
Comprehensive income	191,226	207,823	151,563
Less: comprehensive income (loss) attributable to noncontrolling interests:
Net income attributable to noncontrolling interests	2,515	1,813	2,247
Other Comprehensive (Income) Loss, Net of Tax, Portion Attributable to Noncontrolling Interest	168	426	(33)
Comprehensive income attributable to noncontrolling interests	2,683	2,239	2,214
Comprehensive income attributable to the Company	$ 188,543	$ 205,584	$ 149,349