Debt (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

The following tables summarize the Company’s unsecured note balances and certain interest rate and maturity date information as of and for the years ended December 31, 2016 and 2015, respectively:

December 31, 2016 (Amounts in thousands)	Net Principal Balance		Interest Rate Ranges	Weighted Average Interest Rate	Maturity Date Ranges
Fixed Rate Public Notes (1)	$	4,397,829	2.85% - 7.57%	4.90%	2017 - 2045
Floating Rate Public Notes (1)	450,250		(1)	1.28%	2019
Totals	$	4,848,079

December 31, 2015 (Amounts in thousands)	Net Principal Balance		Interest Rate Ranges	Weighted Average Interest Rate	Maturity Date Ranges
Fixed Rate Public Notes (1)	$	5,397,552	3.00% - 7.57%	5.30%	2016 - 2045
Floating Rate Public Notes (1)	451,404		(1)	0.93%	2019
Totals	$	5,848,956

(1) Fair value interest rate swaps convert the $450.0 million2.375% notes due July 1, 2019 to a floating interest rate of 90-Day LIBOR plus 0.61%.

Aggregate payments of principal on unsecured notes payable

The following table provides a summary of the aggregate payments of principal on all debt for each of the next five years and thereafter as of December 31, 2016 (amounts in thousands):

Year	Total
2017	$	628,458
2018	184,369
2019	1,286,037
2020	1,690,090
2021	941,157
Thereafter	4,366,516
Deferred Financing Costs	(42,617		)
Net Unamortized (Discount)	(66,752		)
Total	$	8,987,258