XML 95 R80.htm IDEA: XBRL DOCUMENT v3.8.0.1
Other - Additional Information (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Other [Line Items]      
Depreciation charge $ 6,600 $ 8,000 $ 7,200
Accumulated depreciation and amortization 104,817 102,794  
Assets Held under Capital Leases      
Other [Line Items]      
Machinery, furniture and equipment 2,000 2,200  
Accumulated depreciation and amortization $ 1,900 2,000  
Depreciation Adjustment      
Other [Line Items]      
Depreciation charge   $ 1,200