Intangibles (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Intangible assets:
Acquired lease intangibles	$ 1,502,955	$ 1,548,074
Goodwill	1,050,548	1,034,644
Accumulated amortization	(921,107)	(864,576)
Net intangible assets	$ 1,668,155	$ 1,754,032
Remaining weighted average amortization period in years	22 years 10 months 24 days	22 years 1 month 6 days
Intangible liabilities:
Below market lease intangibles	$ 356,771	$ 359,118
Other lease intangibles	31,418	40,141
Accumulated amortization	(191,909)	(160,985)
Purchase option intangibles	3,568	3,568
Net intangible liabilities	$ 199,848	$ 241,842
Below market leases, remaining weighted average amortization period	14 years 4 months 24 days	13 years 8 months 12 days
Other lease intangibles, remaining weighted average amortization period	46 years 6 months	40 years 9 months 18 days
Net intangible liabilities, remaining weighted average amortization period	17 years 2 months 12 days	15 years 7 months 6 days
Intangibles
Net amortization expense	$ 49,200	$ 67,200	$ 104,500
Estimated net amortization of the intangibles during 2019	55,502
Estimated net amortization of the intangibles during 2020	44,192
Estimated net amortization of the intangibles during 2021	38,450
Estimated net amortization of the intangibles during 2022	30,092
Estimated net amortization of the intangibles during 2023	26,022
Above Market Lease Intangibles
Intangible assets:
Acquired lease intangibles	$ 181,393	$ 185,012
Remaining weighted average amortization period in years	6 years 8 months 12 days	7 years
In-Place and Other Lease Intangibles
Intangible assets:
Acquired lease intangibles	$ 1,321,562	$ 1,363,062
Remaining weighted average amortization period in years	24 years 8 months 12 days	24 years
Other Intangibles
Intangible assets:
Other finite-lived intangible assets	$ 35,759	$ 35,890
Remaining weighted average amortization period in years	11 years 9 months 18 days	14 years 1 month 6 days