Leases (Tables)

12 Months Ended

Dec. 31, 2017

Operating Leased Assets [Line Items]

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]

Future minimum rent under operating leases in effect at December 31, 2017 for operating centers assuming no new or renegotiated leases or option extensions on anchor agreements, is summarized as follows:

2018	$	332,593
2019	318,103
2020	292,463
2021	254,603
2022	215,625
Thereafter	664,727

Lessee, Operating Lease, Disclosure [Table Text Block]

The following is a schedule of future minimum rental payments required under operating leases:

2018	$	15,484
2019	15,427
2020	14,288
2021	12,740
2022	13,982
Thereafter	737,210