Fair Value Measurements (Financial Assets and Liabilities Not Measured at Fair Value) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Carrying Amount
Assets
Cash Equivalents	$ 273,477	$ 256,730
Liabilities
Mortgages payable (excluding deferred debt issuance costs, net)	1,055,246	1,056,147
Fair Value \| Level 1
Assets
Cash Equivalents	273,477	256,730
Fair Value \| Level 2
Liabilities
Mortgages payable (excluding deferred debt issuance costs, net)	$ 1,042,000	$ 1,045,000

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant