Accumulated Other Comprehensive Income - AOCI Rollforward with Reclassification (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 24,258	$ 50,727
Beginning balance, as adjusted			$ 50,073
Other comprehensive (loss) income	(5,409)	4,124
Ending balance	13,954	24,258
Unrealized Gains (Losses) on Available-for-Sale Investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(160)	(566)
Cumulative effect of adoption of ASU			40
Beginning balance, as adjusted				$ (526)
Other comprehensive income (loss) arising during the period	247	13
Amounts reclassified from accumulated other comprehensive income	(28)	(18)
Amounts removed from accumulated other comprehensive income due to disposal of discontinued operations		371
Other comprehensive (loss) income	219	366
Ending balance	59	(160)
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(3,286)	(3,286)
Cumulative effect of adoption of ASU			0
Beginning balance, as adjusted				(3,286)
Other comprehensive income (loss) arising during the period	0	0
Amounts reclassified from accumulated other comprehensive income	0	0
Amounts removed from accumulated other comprehensive income due to disposal of discontinued operations		0
Other comprehensive (loss) income	0	0
Ending balance	(3,286)	(3,286)
Change in Fair Value of Debt Attributable to Instrument-Specific Credit Risk
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	44,259	0
Cumulative effect of adoption of ASU			40,455
Beginning balance, as adjusted				40,455
Other comprehensive income (loss) arising during the period	(5,685)	3,804
Amounts reclassified from accumulated other comprehensive income	0	0
Amounts removed from accumulated other comprehensive income due to disposal of discontinued operations		0
Other comprehensive (loss) income	(5,685)	3,804
Ending balance	38,574	44,259
Equity in Other Comprehensive Loss of Limited Liability Investment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(45)	0
Cumulative effect of adoption of ASU			0
Beginning balance, as adjusted				0
Other comprehensive income (loss) arising during the period	0	(45)
Amounts reclassified from accumulated other comprehensive income	45	0
Amounts removed from accumulated other comprehensive income due to disposal of discontinued operations		0
Other comprehensive (loss) income	45	(45)
Ending balance	0	(45)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	40,768	(3,852)
Cumulative effect of adoption of ASU			40,495
Beginning balance, as adjusted			$ 36,643	$ 36,643
Other comprehensive income (loss) arising during the period	(5,438)	3,772
Amounts reclassified from accumulated other comprehensive income	17	(18)
Amounts removed from accumulated other comprehensive income due to disposal of discontinued operations		371
Other comprehensive (loss) income	(5,421)	4,125
Ending balance	$ 35,347	$ 40,768