Composition of Corporate and Unallocated Costs (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Corporate and unallocated costs	$ 146,577	$ 130,172	$ 305,722	$ 251,527
Cost of sales
Segment Reporting Information [Line Items]
Corporate and unallocated costs	17,383	13,549	54,181	28,022
Selling, general and administrative expenses
Segment Reporting Information [Line Items]
Corporate and unallocated costs	100,820	92,191	194,491	175,846
Research and development expenses
Segment Reporting Information [Line Items]
Corporate and unallocated costs	$ 28,374	$ 24,432	$ 57,050	$ 47,659