Derivative instruments and hedging activities - Narrative (Details) $ in Millions	6 Months Ended
Jun. 30, 2020 USD ($)
Interest rate swaps
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net deferred losses from accumulated other comprehensive loss	$ 5.7

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121549185&loc=d3e80748-113994

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration