Intangible Assets and Liabilities - Summary of Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Assets:
Gross	$ 665,679	$ 728,485
Accumulated amortization	(387,827)	(355,576)
Total	$ 277,852	$ 372,909
Weighted Average Remaining Amortization in Years	9 years 4 months 24 days	22 years 1 month 6 days
Liabilities:
Gross	$ 65,966	$ 82,005
Accumulated amortization	(27,187)	(20,859)
Total	$ 38,779	$ 61,146
Weighted Average Remaining Amortization in Years	13 years 10 months 24 days	25 years 3 months 18 days
Below market leases
Liabilities:
Gross	$ 65,966	$ 61,395
Weighted Average Remaining Amortization in Years	13 years 10 months 24 days	14 years 7 months 6 days
Above market leasehold interests (1)
Liabilities:
Gross	$ 0	$ 20,610
Weighted Average Remaining Amortization in Years		49 years 2 months 12 days
In place leases
Assets:
Gross	$ 481,173	$ 449,424
Weighted Average Remaining Amortization in Years	9 years 6 months	9 years 9 months 18 days
Tenant relationships
Assets:
Gross	$ 146,893	$ 150,440
Weighted Average Remaining Amortization in Years	9 years 8 months 12 days	9 years 4 months 24 days
Above market leases
Assets:
Gross	$ 37,613	$ 36,862
Weighted Average Remaining Amortization in Years	6 years 2 months 12 days	6 years 1 month 6 days
Below market leasehold interests (1)
Assets:
Gross	$ 0	$ 91,759
Weighted Average Remaining Amortization in Years		64 years 3 months 18 days