XML 59 R46.htm IDEA: XBRL DOCUMENT v3.8.0.1
Summary of Significant Accounting Policies - Property and Equipment (Detail) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Accounting Policies [Abstract]        
Depreciation expense related to property and equipment   $ 183,808 $ 170,240 $ 162,845
Accrued capital expenditures   $ 9,600 12,700  
Impairment of long-lived assets to be disposed of $ 8,000   $ 8,000  
Impairment of long-lived assets held-for-use       $ 6,600