XML 44 R31.htm IDEA: XBRL DOCUMENT v3.8.0.1
Summary of Significant Accounting Policies - Cash and Cash Equivalents (Detail) - USD ($)
$ in Thousands
Sep. 30, 2017
Jun. 30, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Dec. 31, 2015
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents $ 91,532 $ 99,565 $ 112,183 $ 117,366 $ 162,344 $ 128,771
Cash equivalents 8,300   8,800      
Domestic Bank Accounts            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 25,000   19,500      
Foreign Bank Accounts            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 66,500   92,700      
Investments in Joint Ventures            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents 34,000   11,500      
Domestic Joint Ventures            
Cash and Cash Equivalents [Line Items]            
Cash and cash equivalents $ 10,000   $ 10,000