Fair Value Measurements (Tables)

3 Months Ended

Mar. 31, 2017

Fair Value Disclosures [Abstract]

Summary of balance sheet fair values

All financial instruments of the Company are reflected in the accompanying Consolidated Balance Sheets at amounts which, in management's estimation, reasonably approximate their fair values, except for the following:

	March 31, 2017			December 31, 2016
(in thousands)	Carrying Amount		Fair Value	Carrying Amount		Fair Value
Financial assets:
Notes receivable	$	10,992	10,877	$	10,481	10,380
Financial liabilities:
Notes payable	$	2,749,202	2,832,355	$	1,363,925	1,435,000
Unsecured credit facilities	$	658,024	660,000	$	278,495	279,700

Fair Value, Interest rate ranges [Table Text Block]

The following interest rate ranges were used by the Company to estimate the fair value of its financial instruments:

	March 31, 2017		December 31, 2016
	Low	High	Low	High
Notes receivable	7.3%	7.3%	7.2%	7.2%
Notes payable	3.0%	3.8%	2.9%	3.9%
Unsecured credit facilities	1.7%	1.7%	1.5%	1.6%

Summary of assets measured on recurring basis

The following tables present the placement in the fair value hierarchy of assets and liabilities that are measured at fair value on a recurring basis:

	Fair Value Measurements as of March 31, 2017
(in thousands)				Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs		Significant Unobservable Inputs
Assets:	Balance			(Level 1)	(Level 2)		(Level 3)
Trading securities held in trust	$	29,025		29,025	—		—
Available-for-sale securities	7,543			—	7,543		—
Interest rate derivatives	12,340			—	12,340		—
Total	$	48,908		29,025	19,883		—
Liabilities:
Interest rate derivatives	$	(1,033	)	—	(1,033	)	—

	Fair Value Measurements as of December 31, 2016
(in thousands)				Quoted Prices in Active Markets for Identical Assets	Significant Other Observable Inputs		Significant Unobservable Inputs
Assets:	Balance			(Level 1)	(Level 2)		(Level 3)
Trading securities held in trust	$	28,588		28,588	—		—
Available-for-sale securities	7,420			—	7,420		—
Interest rate derivatives	11,622			—	11,622		—
Total	$	47,630		28,588	19,042		—
Liabilities:
Interest rate derivatives	$	(580	)	—	(580	)	—