Derivative Instruments - Effective Portion of Gains (Losses) on Interest Rate Swap Agreements (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Effective Portion Recognized in AOCI	$ 0
Effective Portion Reclassified from AOCI	689	$ 102	$ (1,186)
Ineffective Portion		0	(7)
Effective Portion Recognized in AOCI		(2,495)	(19)
Interest expense
Derivative [Line Items]
Effective Portion Recognized in AOCI	0
Effective Portion Reclassified from AOCI	$ 689	102	(1,186)
Ineffective Portion		0	(7)
Effective Portion Recognized in AOCI		$ (2,495)	$ (19)

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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-Publisher FASB
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The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

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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.

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Amount, after tax and before reclassification, of gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

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Amount before tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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