Changes in Accumulated Other Comprehensive Income (loss) by Component Net of Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			$ 3,184,034
Other comprehensive income (loss), net of tax	$ (17,140)	$ (8,417)	(9,174)	$ (1,080)
Balance	3,109,304		3,109,304
Available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			662	137
Other comprehensive income before reclassifications				204
Amounts reclassified from accumulated other comprehensive income (loss)			(662)	58
Other comprehensive income (loss), net of tax			(662)	262
Balance		399		399
Derivative instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			5,589	671
Other comprehensive income before reclassifications			11,316	(456)
Amounts reclassified from accumulated other comprehensive income (loss)			(194)	1,117
Other comprehensive income (loss), net of tax			11,122	661
Balance	16,710	1,332	16,710	1,332
Pension obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			(8,993)	(6,810)
Amounts reclassified from accumulated other comprehensive income (loss)			29	15
Other comprehensive income (loss), net of tax			29	15
Balance	(8,964)	(6,795)	(8,964)	(6,795)
Cumulative translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			7,243	9,281
Other comprehensive income before reclassifications			(19,663)	(2,046)
Other comprehensive income (loss), net of tax			(19,663)	(2,047)
Balance	(12,369)	7,234	(12,369)	7,234
Total Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			4,501	3,279
Other comprehensive income before reclassifications			(8,347)	(2,298)
Amounts reclassified from accumulated other comprehensive income (loss)			(827)	1,190
Other comprehensive income (loss), net of tax			(9,174)	(1,108)
Balance	(4,673)	2,171	(4,673)	2,171
Less AOCI attributable to Non-controlling Interest
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			51	12
Other comprehensive income before reclassifications			(26)	28
Other comprehensive income (loss), net of tax			(26)	28
Balance	25	40	25	40
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance			4,552	3,291
Other comprehensive income before reclassifications			(8,373)	(2,270)
Amounts reclassified from accumulated other comprehensive income (loss)			(827)	1,190
Other comprehensive income (loss), net of tax			(9,200)	(1,080)
Balance	$ (4,648)	$ 2,211	$ (4,648)	$ 2,211