SUPPLEMENTAL CONSOLIDATED BALANCE SHEETS AND STATEMENTS OF OPERATIONS INFORMATION - Schedule of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive income (loss)	$ 39,081	$ 34,602
Reclassification adjustment included in income (loss) from discontinued operations	0
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI for Write-down of Securities, before Tax	0	(106)	$ (1,341)
Other Comprehensive Income (Loss), Defined Benefit Plan, Adjustment for Settlement or Curtailment Gain (Loss), Tax	0	0	583
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	0	0	2
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	106	(12,717)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Foreign currency translation adjustments, beginning balance	34,294	30,962	58,249
Reclassification for impact of U.S. tax rate change		0
Other comprehensive income (loss)	4,858	3,332	(27,287)
Foreign currency translation adjustments, ending balance	39,152	34,294	30,962
Foreign currency translation	4,858
Net unrealized gain (loss) during the period		3,332	(12,382)
Reclassification adjustment included in income (loss) from discontinued operations	0	0	14,905
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	0	(14,905)
Unrealized gain (loss) on available-for-sale securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification for impact of U.S. tax rate change		161
Other comprehensive income (loss)	(379)	(735)	494
Unrealized gain (loss) on available-for-sale securities, beginning balance	308	882	388
Unrealized gain (loss) on available-for-sale securities, ending balance	(71)	308	882
Net unrealized gain (loss) during the period	(379)
Net unrealized gain (loss) during the period		(841)	(1,109)
Reclassification adjustment included in income (loss) from discontinued operations		(106)	(1,603)
Other than Temporary Impairment Losses, Investments, Available-for-sale Securities	0	0	2,944
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	0	106	1,603
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax	0	0	0	$ (585)
Reclassification for impact of U.S. tax rate change		0
Other comprehensive income (loss)	0	0	585
Foreign currency translation	0
Net unrealized gain (loss) during the period		0	0
Reclassification adjustment included in income (loss) from discontinued operations	0	0	(585)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax		0
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification for impact of U.S. tax rate change		161
Other comprehensive income (loss)	4,479	2,597	(26,208)
Accumulated other comprehensive income (loss)	39,081	34,602	31,844	$ 58,052
Net unrealized gain (loss) during the period	4,479	2,491	(13,491)
Reclassification adjustment included in income (loss) from discontinued operations	0	(106)	12,717
Continuing Operations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	4,479	2,597	(9,697)
Foreign currency translation	4,858	3,332	(10,776)
Net unrealized gain (loss) during the period	(379)	(841)	(1,109)
Reclassification adjustment included in income (loss) from discontinued operations	0	0	(187)
Discontinued Operations, Disposed of by Sale
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	2,597	0	(18,485)
Net unrealized gain (loss) during the period	0	0	(1,793)
Reclassification adjustment included in income (loss) from discontinued operations	0	$ 0	(14,718)
Pension Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	$ 0		$ 585