Consolidated Total Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and cash equivalents	$ 127,167	$ 185,488	$ 190,323	$ 161,020
Assets	2,700,549	2,717,752
Operating Segments
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	2,573,382	2,532,264
Operating Segments | Domestic
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	1,830,369	1,778,481
Operating Segments | International
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	359,614	352,898
Operating Segments | Proprietary Products
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	383,399	400,885
Segment Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Cash and cash equivalents	$ 127,167	$ 185,488