Total Revenues Gross Profit and Long Lived Assets Excluding Long Term Deferred Tax Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets
Total revenues	$ 120,576	$ 119,015
Gross profit	97,444	96,192
Long-lived assets	68,448		$ 71,628
Domestic
Revenues from External Customers and Long-Lived Assets
Total revenues	73,454	72,007
Gross profit	58,945	57,583
Long-lived assets	63,966		67,031
EMEA
Revenues from External Customers and Long-Lived Assets
Total revenues	33,766	35,672
Gross profit	27,244	28,882
Long-lived assets	3,096		3,256
Other Regions
Revenues from External Customers and Long-Lived Assets
Total revenues	13,356	11,336
Gross profit	11,255	$ 9,727
Long-lived assets	$ 1,386		$ 1,341