Accumulated Other Comprehensive Income (Loss) (AOCI) (Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance $ (239,000)    
Change in unrealized gains (losses) on securities 51,893    
Change in foreign currency translation adjustment 12,104    
Amortization of net actuarial loss 7,037    
Amortization of prior service cost (1,211)    
Tax effect (22,296) $ (13,900)  
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance (191,473)    
Accumulated other comprehensive loss (191,522)   $ (239,003)
Allocated to noncontrolling interests 49    
Unrealized Gains (Losses) on Securities      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance (16,401)    
Change in unrealized gains (losses) on securities 51,893    
Tax effect (20,066) (11,049)  
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance 15,426    
Accumulated other comprehensive loss 15,377    
Allocated to noncontrolling interests 49    
Foreign Currency Translation Adjustment      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance (57,242)    
Change in foreign currency translation adjustment 12,104    
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance (45,138)    
Accumulated other comprehensive loss (45,138)    
Pension Benefit Adjustment      
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]      
Accumulated other comprehensive income (loss) including non-controlling interest, Beginning Balance (165,357)    
Amortization of net actuarial loss 7,037    
Amortization of prior service cost (1,211)    
Tax effect (2,230) $ (2,851)  
Accumulated other comprehensive income (loss) including non-controlling interest, Ending Balance (161,761)    
Accumulated other comprehensive loss $ (161,761)