Financial instruments - Schedule of Gains and Losses Reclassified from Accumulated Other Comprehensive Loss into Earnings (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings (loss) on derivatives recognized in net earnings:
Change in fair value of financial instruments	$ 15,490	$ (12,631)	$ (29,118)
Interest Rate Swaps [Member]
Earnings (loss) on derivatives recognized in net earnings:
Change in fair value of financial instruments	14,669	(12,631)	(29,118)
Derivative Put Instrument [Member]
Earnings (loss) on derivatives recognized in net earnings:
Change in fair value of financial instruments	821	0	0
Interest Expense [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Loss reclassified from AOCL to net earnings
Depreciation and amortization/Interest expense	(333)	(1,927)	(3,407)
Depreciation and Amortization [Member] \| Reclassification out of Accumulated Other Comprehensive Income [Member]
Loss reclassified from AOCL to net earnings
Depreciation and amortization/Interest expense	$ (784)	$ (932)	$ (966)

Disclosure financial instruments pre tax gain loss reclassified from AOCL to earnings.

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624177-113959

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- Definition

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

+ References

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- References

No definition available.

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