XML 74 R56.htm IDEA: XBRL DOCUMENT v3.8.0.1
Equipment Lease Obligations - Additional Information (Detail) - Equipment - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Capital Leased Assets [Line Items]      
Assets under equipment leases, gross $ 1,484 $ 2,853  
Assets under equipment leases, depreciation expense 255 293 $ 293
Accumulated depreciation, capital leased assets under equipment leases $ 1,013 $ 757