Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Intangible assets:
Goodwill	$ 1,033,225	$ 1,047,497
Accumulated amortization	(769,558)	(655,176)
Net intangible assets	$ 1,810,079	$ 1,772,535
Remaining Weighted Average Amortization Period in Years	21 years 6 months	19 years 2 months 12 days
Intangible liabilities:
Below market lease intangibles	$ 345,103	$ 256,034
Other lease intangibles	40,843	35,925
Accumulated amortization	(133,468)	(113,647)
Purchase option intangibles	3,568	3,568
Net intangible liabilities	$ 256,046	$ 181,880
Below market leases, remaining weighted average amortization period	14 years 1 month	14 years 2 months 12 days
Other lease intangibles, remaining weighted average amortization period	38 years 6 months	30 years 1 month 6 days
Finite-lived intangible liabilities, remaining weighted average amortization period	15 years 10 months 24 days	15 years 7 months 6 days
Intangibles
Net amortization expense	$ 104,500	$ 142,700	$ 74,600
Estimated net amortization of the intangibles during 2017	66,100
Estimated net amortization of the intangibles during 2018	53,700
Estimated net amortization of the intangibles during 2019	44,400
Estimated net amortization of the intangibles during 2020	38,500
Estimated net amortization of the intangibles during 2021	36,200
Other intangibles
Intangible assets:
Other intangibles	$ 35,783	$ 35,792
Remaining Weighted Average Amortization Period in Years	11 years 3 months 18 days	8 years 7 months 6 days
Above market lease intangibles
Intangible assets:
Intangible assets	$ 184,993	$ 155,161
Remaining Weighted Average Amortization Period in Years	6 years 10 months 24 days	7 years
In-place and other lease intangibles
Intangible assets:
Intangible assets	$ 1,325,636	$ 1,189,261
Remaining Weighted Average Amortization Period in Years	23 years 7 months	20 years 10 months 24 days