Employee Benefit Plans (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) $ / Family	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)
Defined Benefit Plan Disclosure [Line Items]
401(k) deferred compensation and profit sharing plan, company contributions	$ 2,152	$ 2,050		$ 1,956
Annual losses per covered family (in dollars per family) | $ / Family	175
Charges to earnings for self-insurance reserve	$ 7,619	5,520		5,234
Postretirement Medical and Life Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in 2023	$ 142
Multi-Employer Pension Plan | Pentegra DB Plan
Defined Benefit Plan Disclosure [Line Items]
Multiemployer plan, total contributions			$ 248,563		$ 253,199
Multiemployer plan, maximum percentage of employer's contributions	5.00%
Multi-Employer Pension Plan | River Valley
Defined Benefit Plan Disclosure [Line Items]
Pension expense	$ 53	66
Certain directors and officers
Defined Benefit Plan Disclosure [Line Items]
Accrued benefits payable	3,212	2,279
Deferred compensation expense	$ 1,143	$ 302		$ 304