XML 50 R39.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investment Securities and Equity Securities with Readily Determinable Fair Values (Fair Value and Gross Unrealized Loss) (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Available for sale:    
Fair value, less than 12 months $ 1,261,691  
Marketable securities, less than 12 months   $ 1,078,610
Unrealized losses, less than 12 Months (23,135)  
Marketable securities, less than 12 Months   (13,417)
Fair value, 12 months or more 1,948,050  
Marketable securities, 12 months or more   2,037,996
Unrealized losses, 12 Months or More 79,773  
Marketable securities   53,050
Fair value, Total 3,209,741  
Marketable securities, Total   3,116,606
Unrealized losses, Total 102,908  
Marketable securities, Total   66,467
Residential mortgage-backed securities    
Available for sale:    
Fair value, less than 12 months 1,246,760 1,061,577
Unrealized losses, less than 12 Months (23,016) (13,157)
Fair value, 12 months or more 1,947,535 2,029,455
Unrealized losses, 12 Months or More 79,762 52,812
Fair value, Total 3,194,295 3,091,032
Unrealized losses, Total 102,778 65,969
Obligations of states and political subdivisions    
Available for sale:    
Fair value, less than 12 months 14,931 5,534
Unrealized losses, less than 12 Months (119) (9)
Fair value, 12 months or more 515 522
Unrealized losses, 12 Months or More 11 7
Fair value, Total 15,446 6,056
Unrealized losses, Total $ 130 16
Equity securities    
Available for sale:    
Equity Securities, less than 12 months   11,499
Equity Securities, less than 12 Months   (251)
Equity Securities, 12 months or more   8,019
Equity Securities   231
Equity Securities, Total   19,518
Equity securities   $ 482