Debt and Derivative Instruments (Schedule of Cash Flow Hedges and Classification on Consolidated Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Other Assets [Member]
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges - interest rate swap agreements	$ 4,955	$ 4,250
Other Liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivatives designated as cash flow hedges - interest rate swap agreements	$ 1,287	$ 1,909

Fair value of all asset derivatives designated as cash flow hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

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- Definition

Fair value of all liability derivatives designated as cash flow hedging instruments.

+ References

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- Definition

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+ References

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