Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
TWL
Regulatory Capital Requirements
Regulatory Capital	$ 40,228	$ 42,317
Regulatory Capital Requirement	1,549	2,396
Excess Regulatory Capital	38,679	39,921
DW
Regulatory Capital Requirements
Regulatory Capital	55,785	52,016
Regulatory Capital Requirement	1,319	2,026
Excess Regulatory Capital	54,466	49,990
TWD
Regulatory Capital Requirements
Regulatory Capital	23,297	33,807
Regulatory Capital Requirement	428	664
Excess Regulatory Capital	22,869	33,143
TEL
Regulatory Capital Requirements
Regulatory Capital	65,029	49,611
Regulatory Capital Requirement	20,448	21,856
Excess Regulatory Capital	44,581	27,755
TWJ
Regulatory Capital Requirements
Regulatory Capital	12,292	11,851
Regulatory Capital Requirement	8,087	8,565
Excess Regulatory Capital	4,205	3,286
TWEU
Regulatory Capital Requirements
Regulatory Capital	6,279	6,217
Regulatory Capital Requirement	1,675	1,701
Excess Regulatory Capital	4,604	4,516
TW SEF
Regulatory Capital Requirements
Financial Resources	30,300	21,303
Required Financial Resources	10,500	10,500
Excess Financial Resources	19,800	10,803
Liquid Financial Assets	13,399	18,168
Required Liquid Financial Assets	5,250	5,250
Excess Liquid Financial Assets	8,149	12,918
DW SEF
Regulatory Capital Requirements
Financial Resources	13,313	13,707
Required Financial Resources	5,807	5,505
Excess Financial Resources	7,506	8,202
Liquid Financial Assets	7,339	7,583
Required Liquid Financial Assets	2,904	2,753
Excess Liquid Financial Assets	$ 4,435	$ 4,830