Debt (Tables)

12 Months Ended

Dec. 31, 2015

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, 2015 and 2014, respectively:

December 31, 2015 (Amounts in thousands)	Net Principal Balance		Interest Rate Ranges	Weighted Average Interest Rate	Maturity Date Ranges
Fixed Rate Public Notes (1)	$	5,423,012	3.00% - 7.57%	5.30%	2016 - 2045
Floating Rate Public Notes (1)	453,340		(1)	0.93%	2019
Totals	$	5,876,352

December 31, 2014 (Amounts in thousands)	Net Principal Balance		Interest Rate Ranges	Weighted Average Interest Rate	Maturity Date Ranges
Fixed Rate Public Notes (1)	$	4,974,154	3.00% - 7.57%	5.45%	2015 - 2044
Floating Rate Public Notes (1)	451,192		(1)	1.15%	2019
Totals	$	5,425,346

(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, 2015 (amounts in thousands):

Year	Total (1)
2016	$	1,352,813
2017	1,347,846
2018	180,461
2019	1,281,127
2020	1,679,432
Thereafter	5,173,079
Net Unamortized (Discount)	(46,260		)
Total	$	10,968,498

(1) Premiums and discounts are amortized over the life of the debt. See Note 18 for discussion of the debt amounts repaid subsequent to December 31, 2015.