XML 50 R41.htm IDEA: XBRL DOCUMENT v3.23.2
Fair Value Measurements - Investments by Contractual Maturity Date (Details) - USD ($)
$ in Thousands
Jun. 30, 2023
Sep. 30, 2022
Amortized Cost, Available-for-sale securities    
Amortized Cost $ 2,140,583 $ 2,162,737
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains 2,368 1,308
Gross unrealized loss (106,718) (113,008)
Fair Value, Available-for-sale securities    
Fair value $ 2,036,233 $ 2,051,037
Yield, Available-for-sale securities    
Yield 4.48% 3.36%
Amortized Cost, Held-to-maturity securities    
Held-to-maturity securities, amortized cost $ 434,172 $ 463,299
Gross Unrealized Gains / Losses, Held-to-maturity securities    
Held-to-maturity securities, gross unrealized gains 16 22
Held-to-maturity securities, gross unrealized losses (49,876) (56,461)
Fair Value, Held-to-maturity securities    
Held-to-maturity securities, fair value $ 384,312 $ 406,860
Yield, Held-to-maturity securities    
Held-to-maturity securities, yield 2.88% 2.88%
Investments $ 2,574,755 $ 2,626,036
Gross unrealized gains on investments 2,384 1,330
Gross unrealized losses on investments (156,594) (169,469)
Total financial assets $ 2,420,545 $ 2,457,897
Yield on investments 4.21% 3.28%
U.S. government and agency securities    
Amortized Cost, Available-for-sale securities    
Amortized cost, within 1 year $ 5,251  
Amortized cost, 1 to 5 years 22,107 $ 40,403
Amortized cost, 5 to 10 years 89,610  
Amortized cost, over 10 years 75,618  
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains, within 1 year 0  
Gross unrealized gains, 1 to 5 years 0 0
Gross unrealized gains, 5 to 10 years 196  
Gross unrealized gains, over 10 years 526  
Gross unrealized losses, Within 1 year (39)  
Gross unrealized losses, 1 to 5 years (674) (1,049)
Gross unrealized losses, 5 to 10 years 0  
Gross unrealized losses, over 10 years (36)  
Fair Value, Available-for-sale securities    
Fair value, within 1 year 5,212  
Fair value, 1 to 5 years 21,433 $ 39,354
Fair value, 5 to 10 years 89,806  
Fair value, over 10 years $ 76,108  
Yield, Available-for-sale securities    
Yield, within 1 year 5.75%  
Yield, 1 to 5 years 4.53% 3.03%
Yield, 5 to 10 years 5.51%  
Yield, over 10 years 5.62%  
Asset-backed securities    
Amortized Cost, Available-for-sale securities    
Amortized cost, 1 to 5 years $ 19,368 $ 22,527
Amortized cost, 5 to 10 years 42,069 82,962
Amortized cost, over 10 years 562,179 668,482
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains, 1 to 5 years 0 0
Gross unrealized gains, 5 to 10 years 7 4
Gross unrealized gains, over 10 years 469 783
Gross unrealized losses, 1 to 5 years (911) (1,141)
Gross unrealized losses, 5 to 10 years (206) (547)
Gross unrealized losses, over 10 years (11,191) (6,069)
Fair Value, Available-for-sale securities    
Fair value, 1 to 5 years 18,457 21,386
Fair value, 5 to 10 years 41,870 82,419
Fair value, over 10 years $ 551,457 $ 663,196
Yield, Available-for-sale securities    
Yield, 1 to 5 years 5.78% 3.27%
Yield, 5 to 10 years 5.88% 3.53%
Yield, over 10 years 6.10% 3.86%
Corporate debt securities    
Amortized Cost, Available-for-sale securities    
Amortized cost, within 1 year   $ 75,000
Amortized cost, 1 to 5 years $ 151,772 151,411
Amortized cost, 5 to 10 years 113,519 114,414
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains, within 1 year   4
Gross unrealized gains, 1 to 5 years 1,105 0
Gross unrealized gains, 5 to 10 years 0 0
Gross unrealized losses, Within 1 year   (200)
Gross unrealized losses, 1 to 5 years (1,882) (2,748)
Gross unrealized losses, 5 to 10 years (17,883) (24,124)
Fair Value, Available-for-sale securities    
Fair value, within 1 year   74,804
Fair value, 1 to 5 years 150,995 148,663
Fair value, 5 to 10 years $ 95,636 $ 90,290
Yield, Available-for-sale securities    
Yield, within 1 year   3.74%
Yield, 1 to 5 years 4.86% 3.59%
Yield, 5 to 10 years 3.87% 3.87%
Municipal bonds due    
Amortized Cost, Available-for-sale securities    
Amortized cost, 5 to 10 years $ 5,728 $ 5,751
Amortized cost, over 10 years 29,842 29,871
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains, 5 to 10 years 0 0
Gross unrealized gains, over 10 years 10 400
Gross unrealized losses, 5 to 10 years (218) (361)
Gross unrealized losses, over 10 years (313) (699)
Fair Value, Available-for-sale securities    
Fair value, 5 to 10 years 5,510 5,390
Fair value, over 10 years $ 29,539 $ 29,572
Yield, Available-for-sale securities    
Yield, 5 to 10 years 3.00% 3.00%
Yield, over 10 years 5.85% 5.85%
Agency pass-through certificates    
Amortized Cost, Available-for-sale securities    
Amortized cost, without single maturity date $ 1,023,520 $ 971,916
Gross Unrealized Gains / Losses, Available-for-sale securities    
Gross unrealized gains, without single maturity date 55 117
Gross unrealized losses, without single maturity date (73,365) (76,070)
Fair Value, Available-for-sale securities    
Fair value, without single maturity date $ 950,210 $ 895,963
Yield, Available-for-sale securities    
Yield, without single maturity date 3.30% 2.81%
Amortized Cost, Held-to-maturity securities    
Held-to-maturity securities, amortized cost $ 434,172 $ 463,299
Gross Unrealized Gains / Losses, Held-to-maturity securities    
Held-to-maturity securities, gross unrealized gains 16 22
Held-to-maturity securities, gross unrealized losses (49,876) (56,461)
Fair Value, Held-to-maturity securities    
Held-to-maturity securities, fair value $ 384,312 $ 406,860
Yield, Held-to-maturity securities    
Held-to-maturity securities, yield 2.88% 2.88%