Business Combination - Fair Value Measurement of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands			6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2020	Dec. 31, 2019
ACQUISITION CONSIDERATION
Goodwill	$ 2,384,121	$ 2,358,005	$ 2,384,121	$ 2,358,005
Ben LP
ASSETS
Loans receivable	206,228	232,344	206,228	232,344
Fees receivable	29,168	29,168	29,168	29,168
Investment in public equity securities	24,550	24,550	24,550	24,550
Other assets	14,053	14,053	14,053	14,053
Intangible assets	3,449	3,449	3,449	3,449
Total identifiable assets acquired	277,448	303,564	277,448	303,564
LIABILITIES
Other borrowings	153,086	153,086	153,086	153,086
Commercial loan agreement from parent	168,420	168,420	168,420	168,420
Other liabilities and deferred revenue	105,866	105,866	105,866	105,866
Accounts payable and accrued expenses	13,713	13,713	13,713	13,713
Total liabilities assumed	441,085	441,085	441,085	441,085
Net liabilities assumed	(163,637)	(137,521)	(163,637)	(137,521)
NONCONTROLLING INTERESTS
Common Units not owned by GWG Holdings	181,383	181,383	181,383	181,383
Class S Ordinary Units	85,448	85,448	85,448	85,448
Class S Preferred Units	17	17	17	17
Preferred Series A Subclass 1 Unit Accounts	1,269,654	1,269,654	1,269,654	1,269,654
Total noncontrolling interests	1,536,502	1,536,502	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		622,500
Fair value of noncontrolling interest	1,536,502	1,536,502	1,536,502	1,536,502
Total estimated consideration	2,220,484	2,220,484
Less: Net liabilities assumed	(163,637)	(137,521)	(163,637)	(137,521)
Goodwill	$ 2,384,121	$ 2,358,005	2,384,121	$ 2,358,005
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