XML 90 R77.htm IDEA: XBRL DOCUMENT v3.7.0.1
Long-Term Debt - Other - Additional Information (Detail) - Promissory Note - Tremont - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Interest rate 3.00%  
Principal prepayments of note $ 2.6 $ 0.3
Principal amount of promissory note $ 19.1  
Loans maturity period Dec. 31, 2023