Investment Securities (Components Of Investment Securities) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 64,489,000	$ 50,008,000
Debt Securities, Trading and Available-for-sale	$ 68,937,000	$ 54,824,000
Weighted average coupon	5.01%	4.85%
Weighted average yield	4.68%	4.41%
Future Prepayment Rate Assumption Of Investment Portfolio	13.20%	11.40%
Fannie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 34,610,000	$ 29,404,000
Debt Securities, Trading and Available-for-sale	$ 38,042,000	$ 33,119,000
Weighted average coupon	4.81%	4.68%
Weighted average yield	4.44%	4.22%
Freddie Mac [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 28,957,000	$ 19,293,000
Debt Securities, Trading and Available-for-sale	$ 29,972,000	$ 20,393,000
Weighted average coupon	5.13%	4.90%
Weighted average yield	4.86%	4.53%
Ginnie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 29,000	$ 281,000
Debt Securities, Trading and Available-for-sale	$ 30,000	$ 282,000
Weighted average coupon	4.51%	4.94%
Weighted average yield	4.98%	5.16%
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 15,000	$ 34,000
Debt Securities, Trading and Available-for-sale	$ 15,000	$ 34,000
Weighted average coupon	5.28%	4.61%
Weighted average yield	6.69%	4.92%
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 258,000	$ 273,000
Debt Securities, Trading and Available-for-sale	$ 258,000	$ 273,000
Weighted average coupon	6.68%	7.27%
Weighted average yield	7.40%	7.04%
Credit Risk Transfer Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading	$ 620,000	$ 723,000
Debt Securities, Trading and Available-for-sale	$ 620,000
Weighted average coupon	11.20%	10.45%
Weighted average yield	8.96%	8.87%
Available-for-sale Securities [Member]
Schedule of Investments [Line Items]
Par value 2	$ 4,591,000	$ 5,034,000
Debt Securities, Available-for-Sale, Unamortized discount	1,000	1,000
Debt Securities, Available-for-Sale, Unamortized premium	270,000	300,000
Debt Securities, Available-for-sale, Amortized Cost	4,860,000	5,333,000
Debt Securities, Available-for-Sale, Gross Unrealized Losses	412,000	517,000
Total available-for-sale securities, at fair value	4,448,000	4,816,000
Debt Securities, Available-for-Sale, Gross Unrealized Gains	0	0
Available-for-sale Securities [Member] | Fannie Mae [Member]
Schedule of Investments [Line Items]
Par value 2	3,541,000	3,881,000
Debt Securities, Available-for-Sale, Unamortized discount	1,000	1,000
Debt Securities, Available-for-Sale, Unamortized premium	204,000	227,000
Debt Securities, Available-for-sale, Amortized Cost	3,744,000	4,107,000
Debt Securities, Available-for-Sale, Gross Unrealized Losses	312,000	392,000
Total available-for-sale securities, at fair value	3,432,000	3,715,000
Debt Securities, Available-for-Sale, Gross Unrealized Gains	0	0
Available-for-sale Securities [Member] | Freddie Mac [Member]
Schedule of Investments [Line Items]
Par value 2	1,049,000	1,152,000
Debt Securities, Available-for-Sale, Unamortized discount	0	0
Debt Securities, Available-for-Sale, Unamortized premium	66,000	73,000
Debt Securities, Available-for-sale, Amortized Cost	1,115,000	1,225,000
Debt Securities, Available-for-Sale, Gross Unrealized Losses	100,000	125,000
Total available-for-sale securities, at fair value	1,015,000	1,100,000
Debt Securities, Available-for-Sale, Gross Unrealized Gains	0	0
Available-for-sale Securities [Member] | Ginnie Mae [Member]
Schedule of Investments [Line Items]
Par value 2	1,000	1,000
Debt Securities, Available-for-Sale, Unamortized discount	0	0
Debt Securities, Available-for-Sale, Unamortized premium	0	0
Debt Securities, Available-for-sale, Amortized Cost	1,000	1,000
Debt Securities, Available-for-Sale, Gross Unrealized Losses	0	0
Total available-for-sale securities, at fair value	1,000	1,000
Debt Securities, Available-for-Sale, Gross Unrealized Gains	0	0
Trading Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	807,000	325,000
Debt Securities, Trading Securities, Gross Unrealized Losses	1,419,000	1,949,000
Trading Securities Par	64,441,000	50,726,000
Debt Securities, Trading Securities, Unamortized discount	498,000	189,000
Debt Securities, Trading Securities, Unamortized Premium	1,158,000	1,095,000
Debt Securities, Trading, Amortized Cost	65,101,000	51,632,000
Trading Securities [Member] | Fannie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	405,000	170,000
Debt Securities, Trading Securities, Gross Unrealized Losses	953,000	1,270,000
Trading Securities Par	34,734,000	29,910,000
Debt Securities, Trading Securities, Unamortized discount	270,000	108,000
Debt Securities, Trading Securities, Unamortized Premium	694,000	702,000
Debt Securities, Trading, Amortized Cost	35,158,000	30,504,000
Trading Securities [Member] | Freddie Mac [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	352,000	111,000
Debt Securities, Trading Securities, Gross Unrealized Losses	441,000	638,000
Trading Securities Par	28,811,000	19,503,000
Debt Securities, Trading Securities, Unamortized discount	208,000	59,000
Debt Securities, Trading Securities, Unamortized Premium	443,000	376,000
Debt Securities, Trading, Amortized Cost	29,046,000	19,820,000
Trading Securities [Member] | Ginnie Mae [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	0	1,000
Debt Securities, Trading Securities, Gross Unrealized Losses	0	0
Trading Securities Par	30,000	283,000
Debt Securities, Trading Securities, Unamortized discount	(1,000)	(3,000)
Debt Securities, Trading Securities, Unamortized Premium	0	0
Debt Securities, Trading, Amortized Cost	29,000	280,000
Trading Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	0	0
Debt Securities, Trading Securities, Gross Unrealized Losses	2,000	9,000
Trading Securities Par	19,000	44,000
Debt Securities, Trading Securities, Unamortized discount	3,000	3,000
Debt Securities, Trading Securities, Unamortized Premium	1,000	2,000
Debt Securities, Trading, Amortized Cost	17,000	43,000
Trading Securities [Member] | Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	3,000	2,000
Debt Securities, Trading Securities, Gross Unrealized Losses	23,000	32,000
Trading Securities Par	285,000	307,000
Debt Securities, Trading Securities, Unamortized discount	8,000	7,000
Debt Securities, Trading Securities, Unamortized Premium	1,000	3,000
Debt Securities, Trading, Amortized Cost	278,000	303,000
Trading Securities [Member] | Credit Risk Transfer Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading Securities, Gross Unrealized Gains	47,000	41,000
Debt Securities, Trading Securities, Gross Unrealized Losses	0	0
Trading Securities Par	562,000	679,000
Debt Securities, Trading Securities, Unamortized discount	8,000	9,000
Debt Securities, Trading Securities, Unamortized Premium	19,000	12,000
Debt Securities, Trading, Amortized Cost	573,000	682,000
Securities Remeasured at Fair Value [Member] | Credit Risk Transfer Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale		723,000
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale	15,000	34,000
Commercial Mortgage Backed Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale	258,000	273,000
Credit Risk Transfer Securities [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale	620,000	723,000
Credit Risk Transfer Securities [Member] | Securities Remeasured at Fair Value [Member]
Schedule of Investments [Line Items]
Debt Securities, Trading and Available-for-sale	$ 620,000	$ 723,000