Derivative Instruments - Cash flow hedges (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Effects of derivative instruments
Unrealized (loss) gain on derivative instruments	$ (3,331,000)	$ 533,000
Cash flow hedging
Effects of derivative instruments
Unrealized (loss) gain on derivative instruments	(3,331,000)	533,000
Amount of Gain Reclassified from Accumulated OCI into Income (Effective Portion)	713,000	359,000
Significant ineffectiveness on held hedges	0	0
Cash flow hedging \| Interest rate contracts \| Interest expense
Effects of derivative instruments
Unrealized (loss) gain on derivative instruments	(3,331,000)	533,000
Amount of Gain Reclassified from Accumulated OCI into Income (Effective Portion)	$ 713,000	$ 359,000

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

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

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Amount, before tax, of reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e689-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118930883&loc=d3e637-108580

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5624171-113959

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Represents the portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing the amount of significant hedge ineffectiveness.

+ References

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