XML 52 R41.htm IDEA: XBRL DOCUMENT v3.10.0.1
INVESTMENTS - Age of Gross Unrealized Losses and Associated Fair Value by Investment Category (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value $ 1,920,376 $ 570,095
Less than 12 Months Unrealized Loss (28,443) (4,745)
12 Months or More Fair Value 494,421 335,516
12 Months or More Unrealized Loss (23,936) (8,881)
Total Fair Value 2,414,797 905,611
Total Unrealized Loss (52,379) (13,626)
U.S. Treasuries    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 0 97
Less than 12 Months Unrealized Loss 0 (1)
12 Months or More Fair Value 95 0
12 Months or More Unrealized Loss (4) 0
Total Fair Value 95 97
Total Unrealized Loss (4) (1)
Securities of U.S. government agencies and corporations    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 19,546 11,092
Less than 12 Months Unrealized Loss (411) (76)
12 Months or More Fair Value 5,332 0
12 Months or More Unrealized Loss (189) 0
Total Fair Value 24,878 11,092
Total Unrealized Loss (600) (76)
Residential Mortgage Backed Securities [Member]    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 431,332 175,183
Less than 12 Months Unrealized Loss (8,695) (1,109)
12 Months or More Fair Value 141,519 108,782
12 Months or More Unrealized Loss (7,182) (3,025)
Total Fair Value 572,851 283,965
Total Unrealized Loss (15,877) (4,134)
Commercial Mortgage Backed Securities [Member]    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 281,842 132,818
Less than 12 Months Unrealized Loss (3,637) (1,713)
12 Months or More Fair Value 151,185 72,139
12 Months or More Unrealized Loss (8,387) (2,704)
Total Fair Value 433,027 204,957
Total Unrealized Loss (12,024) (4,417)
Collateralized Mortgage Backed Securities [Member]    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 658,749 164,909
Less than 12 Months Unrealized Loss (10,407) (1,138)
12 Months or More Fair Value 133,153 101,436
12 Months or More Unrealized Loss (5,756) (2,325)
Total Fair Value 791,902 266,345
Total Unrealized Loss (16,163) (3,463)
Obligations of state and other political subdivisions    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 304,298 38,450
Less than 12 Months Unrealized Loss (3,976) (507)
12 Months or More Fair Value 37,683 21,639
12 Months or More Unrealized Loss (1,936) (435)
Total Fair Value 341,981 60,089
Total Unrealized Loss (5,912) (942)
Asset-backed Securities [Member]    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 206,708 44,941
Less than 12 Months Unrealized Loss (1,125) (200)
12 Months or More Fair Value 20,776 24,396
12 Months or More Unrealized Loss (374) (106)
Total Fair Value 227,484 69,337
Total Unrealized Loss (1,499) (306)
Other securities    
Investments, Unrealized Loss Position [Line Items]    
Less than 12 Months Fair Value 17,901 2,605
Less than 12 Months Unrealized Loss (192) (1)
12 Months or More Fair Value 4,678 7,124
12 Months or More Unrealized Loss (108) (286)
Total Fair Value 22,579 9,729
Total Unrealized Loss $ (300) $ (287)