Loans and Allowance for Credit Losses: Loans and Unfunded Credit Commitments - Activity in Allowance for Unfunded Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Increase in ACL for unfunded commitments	$ (214,000)
Allowance for credit loss, beginning balance	422,000	$ 448,000	$ 305,000
Provision for credit losses	288,000	66,000	189,000
Foreign currency translation adjustments	(3,000)		3,000
Allowance for credit loss, ending balance	636,000	422,000	448,000
Impact of Adopting ASC 326
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss, beginning balance			25,000
Unfunded credit commitments
Financing Receivable, Allowance for Credit Loss [Line Items]
Increase in ACL for unfunded commitments	132,000
Allowance for credit loss, beginning balance	171,000	121,000	68,000
Provision for credit losses	133,000	50,000	30,000
Foreign currency translation adjustments	(1,000)	0	0
Allowance for credit loss, ending balance	303,000	171,000	121,000
Unfunded credit commitments | Impact of Adopting ASC 326
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit loss, beginning balance	$ 0	0	23,000
Allowance for credit loss, ending balance		$ 0	$ 0