XML 51 R37.htm IDEA: XBRL DOCUMENT v3.5.0.2
Investments - Additional Information (Detail) - USD ($)
9 Months Ended
Sep. 30, 2016
Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]    
Equity securities, Unrealized loss position twelve months or longer $ 27,714,000 $ 30,080,000
Equity securities, Unrealized loss 2,600,000  
Equity Securities [Member]    
Schedule Of Available For Sale Securities [Line Items]    
Equity securities, Unrealized loss position twelve months or longer 12,000,000  
OTTI losses on equity portfolio $ 0