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Derivatives - Fair Value Measurements on Recurring Basis (Details) - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
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2014 Swaps |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | $ (333) | $ (1,478)
2014 Swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 | 0
2014 Swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | (333) | (1,478)
2014 Swaps | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 | 0
2015 Swaps |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | (7,317) | (1,711)
2015 Swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 | 0
2015 Swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | (7,317) | (1,711)
2015 Swaps | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 | $ 0
2021 Swaps |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | (6,244) |
2021 Swaps | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 |
2021 Swaps | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | (6,244) |
2021 Swaps | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |  |
Fair Value On Recurring Basis [Line Items] |  |
Hedging Instrument, Liability, Fair Value | 0 |
2020 Swap |  |
Fair Value On Recurring Basis [Line Items] |  |
Derivative Not Designated as Hedging Instrument, Liability, Fair Value | (106) |
2020 Swap | Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1) |  |
Fair Value On Recurring Basis [Line Items] |  |
Derivative Not Designated as Hedging Instrument, Liability, Fair Value | 0 |
2020 Swap | Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2) |  |
Fair Value On Recurring Basis [Line Items] |  |
Derivative Not Designated as Hedging Instrument, Liability, Fair Value | (106) |
2020 Swap | Fair Value, Measurements, Recurring | Unobservable Inputs (Level 3) |  |
Fair Value On Recurring Basis [Line Items] |  |
Derivative Not Designated as Hedging Instrument, Liability, Fair Value | $ 0 |

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- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
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