Derivatives - Fair Value Measurements on Recurring Basis (Details) $ in Thousands	Sep. 30, 2017 USD ($)
2015 Swaps
Derivatives, Fair Value [Line Items]
Hedging Instrument, Asset, Fair Value	$ 1,174
2015 Swaps \| Fair Value, Measurements, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Asset, Fair Value	0
2015 Swaps \| Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Asset, Fair Value	1,174
2015 Swaps \| Fair Value, Measurements, Recurring \| Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Asset, Fair Value	0
2014 Swaps
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	(3,405)
2014 Swaps \| Fair Value, Measurements, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	0
2014 Swaps \| Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	(3,405)
2014 Swaps \| Fair Value, Measurements, Recurring \| Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	0
Treasury Lock
Derivatives, Fair Value [Line Items]
Instruments Not Designated as Hedging, Asset, at Fair Value	1,848
Treasury Lock \| Fair Value, Measurements, Recurring \| Quoted Prices in Active Markets for Identical Assets (Level 1)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	0
Treasury Lock \| Fair Value, Measurements, Recurring \| Significant Other Observable Inputs (Level 2)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	(1,848)
Treasury Lock \| Fair Value, Measurements, Recurring \| Unobservable Inputs (Level 3)
Derivatives, Fair Value [Line Items]
Hedging Instrument, Liability, Fair Value	$ 0

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=84234895&loc=SL5624163-113959

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

+ Details

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- Definition

Fair value as of the balance sheet date of derivative instrument not designated as hedging instrument and classified as an asset.

+ References

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)(2)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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