Reconciliation of Net Income to Adjusted Segment Earnings before Interest, Taxes, Depreciation and Amortization (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Segment Reporting [Abstract]
Net income	$ 14,016	$ 30,181
Income tax provision	7,877	18,386
Interest income and other	(605)	(2,557)
Interest expense	5,801	6,229
Unallocated corporate expenses	19,053	18,746
Segment depreciation expense	7,216	7,029
Amortization of intangible assets	2,493	2,606
Segment special charges		5,061
Remeasurement of acquisition-related contingent consideration	166	980
Total Adjusted Segment EBITDA	$ 56,017	$ 86,661