Derivatives and Hedging Activities - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative [Line Items]
Foreign currency translation adjustment (CTA) gain (loss)	$ 100,909	$ (32,603)	$ 408,830	$ (215,065)
Gains (losses) reclassified from AOCI to revenues		10,100	25,800	22,700
Losses reclassified from AOCI into income, effective portion		(5,000)	(13,400)	(11,700)
Gain (loss) recognized in income, ineffective portion and amount excluded from effectiveness testing, net			3,600	3,600
Designated as hedging instruments [Member]
Derivative [Line Items]
Total principal amount of foreign currency loans designated as net investment hedges	2,499,400		2,499,400		$ 646,200
Foreign currency translation adjustment (CTA) gain (loss)	(60,700)	5,500	(191,100)	44,400
Net foreign exchange gains, gains on sale of discontinued operations		40,000		40,000
Not designated as hedging instruments [Member] | Embedded derivatives [Member]
Derivative [Line Items]
Net gains (losses) on embedded derivatives			(6,300)	(7,300)
Not designated as hedging instruments [Member] | Economic hedges of embedded derivatives [Member]
Derivative [Line Items]
Net gains (losses) on embedded derivatives				5,300
Not designated as hedging instruments [Member] | Foreign currency forward and option contracts [Member]
Derivative [Line Items]
Net gain (loss) in foreign currency forward and options contracts	$ (23,066)	$ 3,169	$ (60,248)	$ 44,649