Investment Securities - HTM (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
HTM Securities
Amortized Cost Basis	$ 704,691	$ 691,746
Credit Loss Allowance	(3,385)	(8,610)
Net Carrying Amount	701,306	683,136
Gross Unrealized Holding Gains	879	1,206
Gross Unrealized Holding Losses	(28,186)	(27,478)
Fair Value	673,999	656,864
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2021	8,610
Credit loss provision (reversal), net	(5,225)
Credit loss allowance at March 31, 2022	3,385
HTM preferred equity interests
Less than one year	405,387
One to three years	52,873
Three to five years	212,450
Thereafter	30,596
Total	701,306
CMBS
HTM Securities
Amortized Cost Basis	533,372	538,506
Credit Loss Allowance	(228)	(3,140)
Net Carrying Amount	533,144	535,366
Gross Unrealized Holding Gains	0	195
Gross Unrealized Holding Losses	(25,218)	(25,029)
Fair Value	507,926	510,532
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2021	3,140
Credit loss provision (reversal), net	(2,912)
Credit loss allowance at March 31, 2022	228
HTM preferred equity interests
Less than one year	313,993
One to three years	25,303
Three to five years	193,848
Thereafter	0
Total	533,144
Preferred interests
HTM Securities
Amortized Cost Basis	119,136	118,409
Credit Loss Allowance	(172)	(2,562)
Net Carrying Amount	118,964	115,847
Gross Unrealized Holding Gains	353	450
Gross Unrealized Holding Losses	(2,921)	(2,449)
Fair Value	116,396	113,848
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2021	2,562
Credit loss provision (reversal), net	(2,390)
Credit loss allowance at March 31, 2022	172
HTM preferred equity interests
Less than one year	91,394
One to three years	27,570
Three to five years	0
Thereafter	0
Total	118,964
Infrastructure bonds
HTM Securities
Amortized Cost Basis	52,183	34,831
Credit Loss Allowance	(2,985)	(2,908)
Net Carrying Amount	49,198	31,923
Gross Unrealized Holding Gains	526	561
Gross Unrealized Holding Losses	(47)	0
Fair Value	49,677	$ 32,484
Activity in credit loss allowance for HTM debt securities
Credit loss allowance at December 31, 2021	2,908
Credit loss provision (reversal), net	77
Credit loss allowance at March 31, 2022	2,985
HTM preferred equity interests
Less than one year	0
One to three years	0
Three to five years	18,602
Thereafter	30,596
Total	$ 49,198