Other Asset and Other Liabilities - Intangible assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-lived intangible assets	$ 5,986
Total Intangible Assets	6,986	$ 8,309
Amortization expense	1,300	500
Total Accumulated Amortization	2,597
Future amortization of lease intangibles
2021	1,295
2022	1,268
2023	1,242
2024	1,032
2025	787
Thereafter	362
Net amount	5,986
SBA license
Indefinite-lived intangible assets	1,000	1,000
Internally developed software | Knight Capital
Finite-lived intangible assets	$ 3,061	3,694
Estimated Useful Life	6 years
Total Accumulated Amortization	$ 739
Future amortization of lease intangibles
Net amount	3,061	3,694
Broker network | Knight Capital
Finite-lived intangible assets	$ 889	1,156
Estimated Useful Life	4 years 6 months
Total Accumulated Amortization	$ 311
Future amortization of lease intangibles
Net amount	889	1,156
Trade name | Knight Capital
Finite-lived intangible assets	$ 709	855
Estimated Useful Life	6 years
Total Accumulated Amortization	$ 171
Future amortization of lease intangibles
Net amount	709	855
Trade name | GMFS
Finite-lived intangible assets	$ 559	699
Estimated Useful Life	15 years
Total Accumulated Amortization	$ 664
Future amortization of lease intangibles
Net amount	559	699
Favorable lease
Finite-lived intangible assets	$ 768	905
Estimated Useful Life	12 years
Total Accumulated Amortization	$ 712
Future amortization of lease intangibles
Net amount	$ 768	$ 905