Segment Information - Selected Segment Financial Data, Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Assets	$ 1,799,925	$ 1,975,788
Americas Segment [Member] | United States [Member]
Segment Reporting Information [Line Items]
Assets	1,050,167	1,182,309
Americas Segment [Member] | Other [Member]
Segment Reporting Information [Line Items]
Assets	29,042	33,492
EMEA Segment [Member]
Segment Reporting Information [Line Items]
Assets	609,993	643,275
Asia/Pacific Segment [Member]
Segment Reporting Information [Line Items]
Assets	$ 110,723	$ 116,712