Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
TWL
Regulatory Capital Requirements
Regulatory Capital	$ 42,317	$ 18,986
Regulatory Capital Requirement	2,396	2,698
Excess Regulatory Capital	39,921	16,288
DW
Regulatory Capital Requirements
Regulatory Capital	52,016	41,164
Regulatory Capital Requirement	2,026	1,803
Excess Regulatory Capital	49,990	39,361
TWD
Regulatory Capital Requirements
Regulatory Capital	33,807	24,042
Regulatory Capital Requirement	664	599
Excess Regulatory Capital	33,143	23,443
TEL
Regulatory Capital Requirements
Regulatory Capital	49,611	46,157
Regulatory Capital Requirement	21,856	17,493
Excess Regulatory Capital	27,755	28,664
TWJ
Regulatory Capital Requirements
Regulatory Capital	11,851	10,592
Regulatory Capital Requirement	8,565	3,413
Excess Regulatory Capital	3,286	7,179
TWEU
Regulatory Capital Requirements
Regulatory Capital	6,217
Regulatory Capital Requirement	1,701
Excess Regulatory Capital	4,516
TW SEF
Regulatory Capital Requirements
Financial Resources	21,303	31,232
Required Financial Resources	10,500	10,500
Excess Financial Resources	10,803	20,732
Liquid Financial Assets	18,168	16,662
Required Liquid Financial Assets	5,250	5,250
Excess Liquid Financial Assets	12,918	11,412
DW SEF
Regulatory Capital Requirements
Financial Resources	13,707	17,837
Required Financial Resources	5,505	5,169
Excess Financial Resources	8,202	12,668
Liquid Financial Assets	7,583	11,888
Required Liquid Financial Assets	2,753	2,585
Excess Liquid Financial Assets	$ 4,830	$ 9,303