Notes and Bonds Payable - Mortgage Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Issuance costs	$ (5,620)
Notes and bonds payable	1,264,370	$ 1,424,992
Mortgage notes payable [Member]
Debt Instrument [Line Items]
Mortgage notes	114,934	128,161
Unamortized premium	2,569	2,704
Unaccreted discount	(1,450)	(1,779)
Issuance costs	(436)	(339)
Notes and bonds payable	$ 115,617	$ 128,747

Face (par) amount of debt instrument at time of issuance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

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Amount, after accumulated amortization, of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount, after accumulated amortization, of debt premium.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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