Acquisitions and Divestitures - Narrative (Details) $ in Thousands, shares in Millions					1 Months Ended	3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 11, 2021 USD ($) earnout	Jun. 10, 2021 USD ($) shares	Jan. 15, 2021 USD ($) earnout shares	Jan. 08, 2021 USD ($)	Jan. 31, 2021 shares	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Apr. 21, 2021	Apr. 20, 2021	Mar. 31, 2021	Jan. 15, 2020	Dec. 31, 2019 USD ($)
Acquisitions and Divestitures
Escrow trust balances						$ 32,300		$ 32,300
Gross profit						4,528	$ 714	24,671	$ 1,014
Gain on remeasurement of investment						0	0	2,915	0
Contingent consideration						5,112		5,112		$ 8,960
Amortization expense relating to intangible assets						1,600	$ 700	4,100	$ 1,600
Goodwill						111,458		111,458		$ 1,165					$ 23,344
Transaction costs						$ 600		$ 2,200
Grapevine Logic, Inc. ("Grapevine")
Acquisitions and Divestitures
Percentage of ownership interest												100.00%
FNL Technologies
Acquisitions and Divestitures
Percentage of ownership interest						29.00%		29.00%			29.00%
Amer Global Technology Limited
Acquisitions and Divestitures
Ownership interest disposed										10.00%
Fintalk Media Inc.
Acquisitions and Divestitures
Ownership interest disposed							10.00%
Grapevine Logic, Inc. ("Grapevine") | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Acquisitions and Divestitures
Loss on disposal								$ 1,200
Timios Holdings Corp
Acquisitions and Divestitures
Percentage of voting equity interests acquired				100.00%
Purchase price, net of cash acquired				$ 40,000
Cash acquired from acquisition				6,500
Escrow trust balances				5,100
Purchase price				46,576
Purchase price on cash				46,576
Goodwill				$ 24,252
Timios Holdings Corp | Title and escrow services
Acquisitions and Divestitures
Revenue						$ 15,500		62,400
Net income (loss)						(16,400)		(10,600)
WAVE
Acquisitions and Divestitures
Percentage of voting equity interests acquired													100.00%	100.00%
Escrow trust balances			$ 5,000
Revenue						1,000		5,200
Net income (loss)						(1,200)		(3,200)
Purchase price			55,034
Purchase price on cash			$ 15,000
Number of common stock issued (in shares) | shares			12.6		0.5
Value of common stock issued			$ 40,000
Common stock be held back at closing (in shares) | shares			3.6
Common shares as contingent consideration as of the acquisition			$ 7,700
Number of earnouts | earnout			3
Payment of additional purchase price			$ 30,000
Gross profit			10,000
Contingent consideration						1,519		1,519
Goodwill			$ 34,142
US Hybrid
Acquisitions and Divestitures
Percentage of voting equity interests acquired		100.00%
Escrow trust balances		$ 1,000
Revenue						1,300		1,600
Net income (loss)						(700)		(1,000)
Purchase price		51,016
Purchase price on cash		$ 30,139
Number of common stock issued (in shares) | shares		6.6
Value of common stock issued		$ 20,900
Common stock be held back at closing (in shares) | shares		6.6
Escrow deposit period		90 days
Performance and retention plan amount		$ 16,700
Goodwill		41,446
US Hybrid | Previously Reported
Acquisitions and Divestitures
Purchase price		50,000
Purchase price on cash		$ 30,000
Solectrac
Acquisitions and Divestitures
Percentage of voting equity interests acquired	78.60%
Escrow trust balances	$ 2,000
Revenue						200		400
Net income (loss)						(700)		(700)
Purchase price	24,671
Purchase price on cash	$ 17,745
Number of earnouts | earnout	3,000
Performance and retention plan amount	$ 6,000
Percent of battery power	100.00%
Equity interest percentage	21.40%
Equity ownership percentage	100.00%
Gain on remeasurement of investment	$ 2,900
Contingent consideration						1,639		1,639
Goodwill	16,787
Solectrac | Employee Performance And Retention Plan
Acquisitions and Divestitures
Performance and retention plan amount	$ 3,000
Acquisitions In 2021
Acquisitions and Divestitures
Amortization expense relating to intangible assets						1,700		4,000
Goodwill						116,600		116,600
VIA Motors International, Inc.
Acquisitions and Divestitures
Transaction costs						$ 3,300		$ 3,300