Business Combination - Fair Value Measurement of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			9 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
ACQUISITION CONSIDERATION
Goodwill		$ 2,358,005	$ 2,384,121
Measurement Period Adjustments
Loans receivable			26,116	$ 0
Ben LP
ASSETS
Loans receivable		232,344	206,228
Fees receivable		29,168	29,168
Investment in public equity securities		24,550	24,550
Other assets		14,053	14,053
Intangible assets		3,449	3,449
Total identifiable assets acquired		303,564	277,448
LIABILITIES
Other borrowings		153,086	153,086
Commercial loan agreement from parent		168,420	168,420
Other liabilities and deferred revenue		105,866	105,866
Accounts payable and accrued expenses		13,713	13,713
Total liabilities assumed		441,085	441,085
Net liabilities assumed		(137,521)	(163,637)
NONCONTROLLING INTERESTS
Common Units not owned by GWG Holdings		181,383	181,383
Class S Ordinary Units		85,448	85,448
Class S Preferred Units		17	17
Preferred Series A Subclass 1 Unit Accounts		1,269,654	1,269,654
Total noncontrolling interests		1,536,502	1,536,502
ACQUISITION CONSIDERATION
Cash, less cash acquired	$ 61,479	61,479
Fair value of preexisting investment in Common Units	622,503	622,503
Fair value of noncontrolling interest		1,536,502	1,536,502
Total estimated consideration	$ 2,220,484	2,220,484
Less: Net liabilities assumed		(137,521)	(163,637)
Goodwill		$ 2,358,005	2,384,121
Measurement Period Adjustments
Loans receivable			(26,116)
Total identifiable assets acquired			(26,116)
Net liabilities assumed			(26,116)
Less: Net liabilities assumed			(26,116)
Resulting preliminary goodwill			$ 26,116