Segmented Information - Segment (loss) income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Total segment operating income	$ 927	$ (1,622)
Net investment income	421	719
Net realized gains	51	208
Loss on change in fair value of equity investments	(151)	(597)
(Loss) gain on change in fair value of limited liability investments, at fair value	(202)	1,899
Net change in unrealized loss on private company investments	0	(670)
Other-than-temporary impairment loss	0	(117)
Interest expense not allocated to segments	(1,552)	(2,153)
Other revenue and expenses not allocated to segments, net	(3,491)	(3,030)
Amortization of intangible assets	(497)	(574)
(Loss) gain on change in fair value of debt	(1,019)	2,645
Gain on extinguishment of debt	2,494	0
Income (loss) before income tax (benefit) expense	474	(223)
Income tax (benefit) expense	(425)	170
Income from continuing operations	899	(393)
Operating Segments
Segment Reporting Information [Line Items]
Total segment operating income	6,603	1,447
Corporate, Non-Segment
Segment Reporting Information [Line Items]
Gain on extinguishment of debt	311	0
Extended Warranty | Operating Segments
Segment Reporting Information [Line Items]
Total segment operating income	5,310	850
Leased Real Estate | Operating Segments
Segment Reporting Information [Line Items]
Total segment operating income	$ 1,293	$ 597