XML 51 R42.htm IDEA: XBRL DOCUMENT v3.23.2
Fair Value Measurements - Securities in Unrealized Loss Positions (Details)
$ in Thousands
Jun. 30, 2023
USD ($)
security
Sep. 30, 2022
USD ($)
security
Debt Securities, Available-for-sale [Line Items]    
Number of debt securities with unrealized loss | security 225 223
Available-for-sale securities    
Less than 12 months, unrealized gross losses $ (7,105) $ (99,294)
12 months or more, unrealized gross losses (99,612) (13,714)
Total unrealized gross losses (106,717) (113,008)
Less than 12 months, fair value 300,141 1,777,599
12 months or more, fair value 1,403,997 103,603
Total, fair value 1,704,138 1,881,202
Held-to-maturity securities    
Less than 12 months, unrealized gross losses (3) (56,461)
Less than 12 months, fair value 713 405,166
12 months or more, unrealized gross losses (49,874) 0
12 months or more, fair value 382,499 0
Total unrealized gross losses (49,877) (56,461)
Total, fair value 383,212 405,166
Less than 12 months, unrealized gross losses (7,108) (155,755)
Less than 12 months, fair value 300,854 2,182,765
12 months or more, unrealized gross losses (149,486) (13,714)
12 months or more, fair value 1,786,496 103,603
Total unrealized gross losses (156,594) (169,469)
Total fair value 2,087,350 2,286,368
Corporate debt securities    
Available-for-sale securities    
Less than 12 months, unrealized gross losses 0 (27,072)
12 months or more, unrealized gross losses (19,764) 0
Total unrealized gross losses (19,764) (27,072)
Less than 12 months, fair value 0 288,753
12 months or more, fair value 151,438 0
Total, fair value 151,438 288,753
Municipal bonds due    
Available-for-sale securities    
Less than 12 months, unrealized gross losses 0 (1,061)
12 months or more, unrealized gross losses (531) 0
Total unrealized gross losses (531) (1,061)
Less than 12 months, fair value 0 14,561
12 months or more, fair value 15,038 0
Total, fair value 15,038 14,561
U.S. government and agency securities    
Available-for-sale securities    
Less than 12 months, unrealized gross losses (36) (1,049)
12 months or more, unrealized gross losses (712) 0
Total unrealized gross losses (748) (1,049)
Less than 12 months, fair value 14,964 39,354
12 months or more, fair value 26,645 0
Total, fair value 41,609 39,354
Asset-backed securities    
Available-for-sale securities    
Less than 12 months, unrealized gross losses (2,406) (6,374)
12 months or more, unrealized gross losses (9,903) (1,383)
Total unrealized gross losses (12,309) (7,757)
Less than 12 months, fair value 79,893 601,248
12 months or more, fair value 515,348 50,070
Total, fair value 595,241 651,318
Mortgage-backed securities    
Available-for-sale securities    
Less than 12 months, unrealized gross losses (4,663) (63,738)
12 months or more, unrealized gross losses (68,702) (12,331)
Total unrealized gross losses (73,365) (76,069)
Less than 12 months, fair value 205,284 833,683
12 months or more, fair value 695,528 53,533
Total, fair value $ 900,812 $ 887,216