Borrowings - Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Oct. 01, 2022 USD ($) item
Assets Sold under Agreements to Repurchase [Line Items]
Amount of repurchase agreements	$ 19,500		$ 19,500		$ 19,600
Fair Value	691,076		691,076		628,829
Remaining balance on the note	54,356		54,356		54,200
Federal home loan bank, advances, general debt obligations, maximum amount available	1,800,000		1,800,000
Loans receivable	7,625,696		7,625,696		7,600,811
Interest expense related to FHLB advances	100	$ 5,600	3,300	$ 12,700
Bank of Jackson Hole
Assets Sold under Agreements to Repurchase [Line Items]
Number of subordinated note purchase agreements assumed | item						3
Asset Pledged as Collateral
Assets Sold under Agreements to Repurchase [Line Items]
Fair Value	0		0		0
Asset Pledged as Collateral | Securities Sold under Agreements to Repurchase
Assets Sold under Agreements to Repurchase [Line Items]
Fair Value	$ 29,900		$ 29,900		$ 30,400
Financing Receivable, Pledging Purpose [Extensible Enumeration]	Noninterest-bearing Deposit Liabilities		Noninterest-bearing Deposit Liabilities		Noninterest-bearing Deposit Liabilities
Excess collateral pledged	$ 10,500		$ 10,500		$ 10,800
Asset Pledged as Collateral | Federal Home Loan Bank Advances
Assets Sold under Agreements to Repurchase [Line Items]
Financing Receivable, Pledging Purpose [Extensible Enumeration]	Noninterest-bearing Deposit Liabilities		Noninterest-bearing Deposit Liabilities
Fair value of available-for-sale investment securities pledged as collateral	$ 0		$ 0		0
Loans receivable	2,600,000		2,600,000		2,600,000
Fixed-To-Floating Rate Note, Maturing June 2031 | Bank of Jackson Hole
Assets Sold under Agreements to Repurchase [Line Items]
Subordinated note						$ 15,000
Fair value adjustment from the acquisition	400		400		500
Remaining balance on the note	14,600		14,600		14,500
Interest expense	100	$ 100	300	300
Line of credit
Assets Sold under Agreements to Repurchase [Line Items]
FHLB advances	35,000		35,000		340,000
Subordinated Debt
Assets Sold under Agreements to Repurchase [Line Items]
Debt issuance costs	300		300
Subordinated Debt | Fixed-To-Floating Rate Note, Maturing November 2031
Assets Sold under Agreements to Repurchase [Line Items]
Subordinated note	$ 40,000		40,000
Remaining balance on the note					$ 39,700
Interest expense			$ 300	$ 600
Interest rate (as a percent)			3.00%
Variable rate basis (as a percent)			203.00%
Redemption price as a percent of principal			100.00%
Subordinated Debt | Fixed-To-Floating Rate Note, Maturing June 2031 | Bank of Jackson Hole
Assets Sold under Agreements to Repurchase [Line Items]
Interest rate (as a percent)			3.75%
Variable rate basis (as a percent)			306.00%
Redemption price as a percent of principal			100.00%