Accumulated other comprehensive (loss) income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Apr. 01, 2018	Jan. 01, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			$ 3,908,398
Ending balance	$ 4,243,069		4,243,069
Interest rate cap and swap agreements
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(7,935)	$ (12,527)	(8,961)	$ (12,408)
Cumulative effect of change in accounting principle					$ 0	$ (2,706)
Unrealized (losses) gains	(42)	(361)	(823)	1,053
Related income tax benefit	11	93	212	(271)
Unrealized (losses) gains net	(31)	(268)	(611)	782
Reclassification into net income	2,163	2,070	4,326	4,140
Related income	(557)	(533)	(1,114)	(1,066)
Reclassification from accumulated other comprehensive income into net income net of tax	1,606	1,537	3,212	3,074
Ending balance	(6,360)	(11,258)	(6,360)	(11,258)
Investment securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				5,662
Cumulative effect of change in accounting principle						(5,662)
Unrealized (losses) gains				0
Related income tax benefit				0
Unrealized (losses) gains net				0
Reclassification into net income				0
Related income				0
Reclassification from accumulated other comprehensive income into net income net of tax				0
Ending balance		0		0
Foreign currency translation adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(39,616)	39,862	(25,963)	19,981
Cumulative effect of change in accounting principle					0	0
Unrealized (losses) gains	12,365	(50,529)	(1,288)	(30,648)
Related income tax benefit	0	0	0	0
Unrealized (losses) gains net	12,365	(50,529)	(1,288)	(30,648)
Reclassification into net income	0	0	0	0
Related income	0	0	0	0
Reclassification from accumulated other comprehensive income into net income net of tax	0	0	0	0
Ending balance	(27,251)	(10,667)	(27,251)	(10,667)
Accumulated other comprehensive (loss) income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(47,551)	27,335	(34,924)	13,235
Cumulative effect of change in accounting principle					$ 0	$ (8,368)
Unrealized (losses) gains	12,323	(50,890)	(2,111)	(29,595)
Related income tax benefit	11	93	212	(271)
Unrealized (losses) gains net	12,334	(50,797)	(1,899)	(29,866)
Reclassification into net income	2,163	2,070	4,326	4,140
Related income	(557)	(533)	(1,114)	(1,066)
Reclassification from accumulated other comprehensive income into net income net of tax	1,606	1,537	3,212	3,074
Ending balance	$ (33,611)	$ (21,925)	$ (33,611)	$ (21,925)