Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
TWL
Regulatory Capital Requirements
Regulatory Capital	$ 37,445	$ 49,254
Regulatory Capital Requirement	1,679	2,438
Excess Regulatory Capital	35,766	46,816
DW
Regulatory Capital Requirements
Regulatory Capital	47,796	58,026
Regulatory Capital Requirement	1,459	2,147
Excess Regulatory Capital	46,337	55,879
TWD
Regulatory Capital Requirements
Regulatory Capital	24,175	20,577
Regulatory Capital Requirement	505	731
Excess Regulatory Capital	23,670	19,846
TEL
Regulatory Capital Requirements
Regulatory Capital	63,682	59,238
Regulatory Capital Requirement	34,164	33,742
Excess Regulatory Capital	29,518	25,496
TESL
Regulatory Capital Requirements
Regulatory Capital	756
Regulatory Capital Requirement	736
Excess Regulatory Capital	20
TWJ
Regulatory Capital Requirements
Regulatory Capital	10,455	11,066
Regulatory Capital Requirement	3,559	3,799
Excess Regulatory Capital	6,896	7,267
TWEU
Regulatory Capital Requirements
Regulatory Capital	8,703	19,102
Regulatory Capital Requirement	2,449	2,562
Excess Regulatory Capital	6,254	16,540
TW SEF
Regulatory Capital Requirements
Financial Resources	44,204	28,476
Required Financial Resources	13,500	13,500
Excess Financial Resources	30,704	14,976
Liquid Financial Assets	27,500	15,662
Required Liquid Financial Assets	6,750	6,750
Excess Liquid Financial Assets	20,750	8,912
DW SEF
Regulatory Capital Requirements
Financial Resources	16,255	15,298
Required Financial Resources	5,991	6,223
Excess Financial Resources	10,264	9,075
Liquid Financial Assets	10,520	8,610
Required Liquid Financial Assets	2,996	3,112
Excess Liquid Financial Assets	$ 7,524	$ 5,498