Loans - Past Due Financing Receivables (Details)	Mar. 31, 2022 USD ($) MortgageLoan	Dec. 31, 2021 Loan	Dec. 31, 2021 USD ($)	Dec. 31, 2021 MortgageLoan	Dec. 31, 2020 Loan	Dec. 31, 2020 USD ($)	Dec. 31, 2020 MortgageLoan
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans		54		0	82		0
Principal			$ 81,097,000			$ 82,275,000
Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans | Loan		47			73
Principal			72,116,000			74,042,000
Past Due 30-89 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans | Loan		4			1
Principal			7,165,000			190,000
Past Due 90-179 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans | Loan		1			5
Principal			930,000			4,757,000
Past Due 180 Or More Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans	1	2			3
Principal	$ 586,000		886,000			3,286,000
Total past due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number of loans | Loan		7			9
Principal			$ 8,981,000			$ 8,233,000