Reconciliation of Net Income (Loss) to Adjusted Segment Earnings before Interest, Taxes, Depreciation and Amortization (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting [Abstract]
Net income (loss)		$ (5,156)	$ 26,547	$ 8,860	$ 56,728
Income tax provision		527	15,437	8,404	33,823
Interest income and other		(1,592)	(4,125)	(2,197)	(6,682)
Interest expense		6,250	6,303	12,051	12,532
Unallocated corporate expenses	[1]	22,286	20,406	41,339	39,152
Segment depreciation expense		6,783	7,179	13,999	14,208
Amortization of intangible assets		2,422	2,590	4,915	5,196
Segment special charges		26,830	1,750	26,830	6,811
Remeasurement of acquisition-related contingent consideration		536		702	980
Total Adjusted Segment EBITDA		$ 58,886	$ 76,087	$ 114,903	$ 162,748

[1] Includes $3.2 million special charges for corporate.