Loans Receivable - Allowance For Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period	$ 1,970	$ 8,719	$ 5,437	$ 2,146
Cumulative effect adjustment resulting from changes in accounting principles	1,737	5,843	1,737	5,843
Provision for expected credit losses	(233)	(2,876)	(3,700)	4,054
Allowance for expected credit losses, end of period	1,737	5,843	1,737	5,843
Cumulative effect adjustment resulting from changes in accounting principles
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period			0	(357)
Cumulative effect adjustment resulting from changes in accounting principles
Real estate loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period	1,501	4,318	1,683	1,502
Cumulative effect adjustment resulting from changes in accounting principles	1,429	1,759	1,429	1,759
Provision for expected credit losses	(72)	(2,559)	(254)	1,162
Allowance for expected credit losses, end of period	1,429	1,759	1,429	1,759
Real estate loans | Cumulative effect adjustment resulting from changes in accounting principles
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period			0	(905)
Cumulative effect adjustment resulting from changes in accounting principles
Commercial loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period	469	4,401	3,754	644
Cumulative effect adjustment resulting from changes in accounting principles	308	4,084	308	4,084
Provision for expected credit losses	(161)	(317)	(3,446)	2,892
Allowance for expected credit losses, end of period	$ 308	$ 4,084	308	4,084
Commercial loans | Cumulative effect adjustment resulting from changes in accounting principles
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for expected credit losses, beginning of period			$ 0	$ 548
Cumulative effect adjustment resulting from changes in accounting principles