Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	$ 2,160,202
Other comprehensive loss before reclassifications	0	$ (447)
Other comprehensive loss, net of tax	0	(447)
Gross amounts reclassified within accumulated other comprehensive income	0	329
Balance	2,197,724
Total Post- Retirement Benefits Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	2,061	2,305
Other comprehensive loss before reclassifications	0	(447)
Other comprehensive loss, net of tax	0	(447)
Gross amounts reclassified within accumulated other comprehensive income	0	0
Balance	2,061	1,858
Foreign Currency Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(79,927)	(79,927)
Other comprehensive loss before reclassifications	0	0
Other comprehensive loss, net of tax	0	0
Gross amounts reclassified within accumulated other comprehensive income	16,479	0
Balance	(63,448)	(79,927)
Non-controlling Interest - Principal Equityholders Reclassification
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	59,877	59,625
Other comprehensive loss before reclassifications	0	0
Other comprehensive loss, net of tax	0	0
Gross amounts reclassified within accumulated other comprehensive income	(16,479)	329
Balance	43,398	59,954
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(17,989)	(17,997)
Balance	$ (17,989)	$ (18,115)