Investment Securities - HTM (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
HTM Securities
Amortized Cost Basis	$ 691,746	$ 544,280
Credit Loss Allowance	(8,610)	(5,675)
Net Carrying Amount	683,136	538,605
Gross Unrealized Holding Gains	1,206	847
Gross Unrealized Holding Losses	(27,478)	(24,199)
Fair Value	656,864	515,253
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2020	5,675
Credit loss provision (reversal), net	2,935
Credit loss allowance at September 30, 2021	8,610
HTM preferred equity interests
Less than one year	404,930
One to three years	47,877
Three to five years	199,213
Thereafter	31,116
Total	683,136
CMBS
HTM Securities
Amortized Cost Basis	538,506	339,059
Credit Loss Allowance	(3,140)	0
Net Carrying Amount	535,366	339,059
Gross Unrealized Holding Gains	195	0
Gross Unrealized Holding Losses	(25,029)	(23,286)
Fair Value	510,532	315,773
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2020	0
Credit loss provision (reversal), net	3,140
Credit loss allowance at September 30, 2021	3,140
HTM preferred equity interests
Less than one year	313,960
One to three years	23,000
Three to five years	198,406
Thereafter	0
Total	535,366
Preferred interests
HTM Securities
Amortized Cost Basis	118,409	166,614
Credit Loss Allowance	(2,562)	(2,749)
Net Carrying Amount	115,847	163,865
Gross Unrealized Holding Gains	450	432
Gross Unrealized Holding Losses	(2,449)	(913)
Fair Value	113,848	163,384
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2020	2,749
Credit loss provision (reversal), net	(187)
Credit loss allowance at September 30, 2021	2,562
HTM preferred equity interests
Less than one year	90,970
One to three years	24,877
Three to five years	0
Thereafter	0
Total	115,847
Infrastructure bonds
HTM Securities
Amortized Cost Basis	34,831	38,607
Credit Loss Allowance	(2,908)	(2,926)
Net Carrying Amount	31,923	35,681
Gross Unrealized Holding Gains	561	415
Gross Unrealized Holding Losses	0	0
Fair Value	32,484	$ 36,096
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2020	2,926
Credit loss provision (reversal), net	(18)
Credit loss allowance at September 30, 2021	2,908
HTM preferred equity interests
Less than one year	0
One to three years	0
Three to five years	807
Thereafter	31,116
Total	$ 31,923