Disclosure of Fair Value of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2018

Debt Instrument, Fair Value Disclosure [Abstract]

Fair Value, by Balance Sheet Grouping [Table Text Block]

The following summarizes the fair value of the Company's mortgage loans and unsecured notes as of December 31, 2017 and June 30, 2018 (in thousands):

	Mortgage Loans				Unsecured Notes
	Carrying Value		Fair Value		Carrying Value		Fair Value
As of December 31, 2017	$	267,093	$	267,298	$	2,283,513	$	2,359,998
As of June 30, 2018	$	235,753	$	265,841	$	2,284,882	$	2,290,029