Derivative financial instruments - Income (loss) recorded in comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Income tax effect	$ (4,088)	$ (2,274)	$ (11,752)	$ (5,339)
Net gain on derivatives, net of tax	28,613	15,920	82,261	37,372
Interest rate swaps
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of change in fair market value of derivatives designated as accounting cash flow hedges:	25,774	17,656	76,524	39,943
Interest rate caps
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of change in fair market value of derivatives designated as accounting cash flow hedges:	5,753	(323)	15,148	1,142
Derivative Premium And Amortization
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion of change in fair market value of derivatives designated as accounting cash flow hedges:	$ 1,174	$ 861	$ 2,341	$ 1,626

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 reclassification, of gain (loss) from 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 11
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e637-108580

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 10A
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=126968391&loc=SL7669646-108580

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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.

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Amount, after reclassification, of tax expense (benefit) for gain (loss) from 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 12
-URI https://asc.fasb.org/extlink&oid=126968391&loc=d3e640-108580

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