XML 53 R39.htm IDEA: XBRL DOCUMENT v3.19.2
Investments (Available-For-Sale Investments) (Details) - USD ($)
$ in Thousands
6 Months Ended
Jun. 30, 2019
Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]    
Document Period End Date Jun. 30, 2019  
Available-for-sale fixed maturity investments, amortized cost $ 11,133,725 $ 11,030,800
Available-for-sale fixed maturity investments, gross unrealized holding gains 525,395 224,073
Available-for-sale fixed maturity investments, gross unrealized holding losses (16,908) (133,989)
Available-for-sale fixed maturity investments, estimated fair value 11,642,212 11,120,884
U.S. Treasury Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 295,201 248,286
Available-for-sale fixed maturity investments, gross unrealized holding gains 2,894 308
Available-for-sale fixed maturity investments, gross unrealized holding losses (422) (1,952)
Available-for-sale fixed maturity investments, estimated fair value 297,673 246,642
U.S. Government-Sponsored Enterprises [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 337,100 357,765
Available-for-sale fixed maturity investments, gross unrealized holding gains 19,863 5,671
Available-for-sale fixed maturity investments, gross unrealized holding losses (104) (4,114)
Available-for-sale fixed maturity investments, estimated fair value 356,859 359,322
Obligations Of States, Municipalities And Political Subdivisions [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 4,140,140 4,285,068
Available-for-sale fixed maturity investments, gross unrealized holding gains 222,904 96,730
Available-for-sale fixed maturity investments, gross unrealized holding losses (847) (28,868)
Available-for-sale fixed maturity investments, estimated fair value 4,362,197 4,352,930
Foreign Governments [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 1,478,894 1,482,826
Available-for-sale fixed maturity investments, gross unrealized holding gains 160,709 98,356
Available-for-sale fixed maturity investments, gross unrealized holding losses (7,028) (21,578)
Available-for-sale fixed maturity investments, estimated fair value 1,632,575 1,559,604
Commercial Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 1,709,453 1,691,572
Available-for-sale fixed maturity investments, gross unrealized holding gains 52,568 3,154
Available-for-sale fixed maturity investments, gross unrealized holding losses (3,999) (44,527)
Available-for-sale fixed maturity investments, estimated fair value 1,758,022 1,650,199
Residential Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 877,279 886,501
Available-for-sale fixed maturity investments, gross unrealized holding gains 34,118 6,170
Available-for-sale fixed maturity investments, gross unrealized holding losses (1,428) (12,499)
Available-for-sale fixed maturity investments, estimated fair value 909,969 880,172
Asset-Backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 11,150 19,614
Available-for-sale fixed maturity investments, gross unrealized holding gains 56 7
Available-for-sale fixed maturity investments, gross unrealized holding losses (10) (213)
Available-for-sale fixed maturity investments, estimated fair value 11,196 19,408
Corporate Bonds [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 902,466 979,141
Available-for-sale fixed maturity investments, gross unrealized holding gains 30,372 13,234
Available-for-sale fixed maturity investments, gross unrealized holding losses (2,689) (17,464)
Available-for-sale fixed maturity investments, estimated fair value 930,149 974,911
Total Fixed Maturities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 9,751,683 9,950,773
Available-for-sale fixed maturity investments, gross unrealized holding gains 523,484 223,630
Available-for-sale fixed maturity investments, gross unrealized holding losses (16,527) (131,215)
Available-for-sale fixed maturity investments, estimated fair value 10,258,640 10,043,188
Short-Term Investments [Member]    
Debt Securities, Available-for-sale [Line Items]    
Available-for-sale fixed maturity investments, amortized cost 1,382,042 1,080,027
Available-for-sale fixed maturity investments, gross unrealized holding gains 1,911 443
Available-for-sale fixed maturity investments, gross unrealized holding losses (381) (2,774)
Available-for-sale fixed maturity investments, estimated fair value $ 1,383,572 $ 1,077,696