Total Revenues Gross Profit and Long-Lived Assets Excluding Long-Term Deferred Tax Assets (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues from External Customers and Long-Lived Assets
Total revenues	$ 140,108	$ 129,896	$ 123,142	$ 119,015	$ 143,522	$ 129,536	$ 132,940	$ 123,871	$ 512,161	$ 529,869	$ 579,830
Gross profit	116,820	$ 106,961	$ 99,041	$ 96,192	120,108	$ 104,852	$ 107,028	$ 96,773	419,014	428,761	444,620
Long-lived assets	71,628				83,591				71,628	83,591
Domestic
Revenues from External Customers and Long-Lived Assets
Total revenues									310,972	326,792	341,692
Gross profit									253,234	265,438	261,459
Long-lived assets	67,031				77,652				67,031	77,652
EMEA
Revenues from External Customers and Long-Lived Assets
Total revenues									150,422	153,658	176,774
Gross profit									122,865	121,148	131,790
Long-lived assets	3,256				3,701				3,256	3,701
Other Regions
Revenues from External Customers and Long-Lived Assets
Total revenues									50,767	49,419	61,364
Gross profit									42,915	42,175	$ 51,371
Long-lived assets	$ 1,341				$ 2,238				$ 1,341	$ 2,238