Condensed Consolidated Statement of Shareholders' Equity Statement - USD ($)	Total	Class B Common Shares [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]
Total Shareholders’ Equity at Dec. 31, 2018	$ 359,147,000	$ 2,000	$ 9,419,000	$ 297,919,000	$ 142,447,000	$ 12,793,000	$ (103,433,000)
Allocated Share-based Compensation Expense	651,000		29,000	970,000			(348,000)
Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition	211,000			211,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	2,581,000		140,000	2,953,000			(512,000)
Net Loss	(26,603,000)				(26,603,000)
Foreign currency translation adjustments	(3,984,000)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(3,984,000)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1,037,000					1,037,000
Amortization of prior service costs and unrecognized (losses) gains	(75,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(75,000)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(29,625,000)
Convertible Debt Derivative Adjustments	(220,000)			(220,000)
Payments of Ordinary Dividends, Common Stock	(819,000)
Dividends, Common Stock, Cash	(819,000)
Total Shareholders’ Equity at Jun. 30, 2019	331,926,000	2,000	9,588,000	301,833,000	115,025,000	9,771,000	(104,293,000)
Total Shareholders’ Equity at Mar. 31, 2019	350,542,000	2,000	9,588,000	299,180,000	128,153,000	17,433,000	(103,814,000)
Allocated Share-based Compensation Expense	534,000		0	534,000			0
Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition	87,000			87,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	1,773,000		0	2,252,000			(479,000)
Net Loss	(12,717,000)				(12,717,000)
Foreign currency translation adjustments	(9,086,000)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	(9,086,000)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	1,525,000					1,525,000
Amortization of prior service costs and unrecognized (losses) gains	(101,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(101,000)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(20,379,000)
Convertible Debt Derivative Adjustments	(220,000)			(220,000)
Payments of Ordinary Dividends, Common Stock	(411,000)
Dividends, Common Stock, Cash	(411,000)
Total Shareholders’ Equity at Jun. 30, 2019	331,926,000	2,000	9,588,000	301,833,000	115,025,000	9,771,000	(104,293,000)
Total Shareholders’ Equity at Dec. 31, 2019	308,516,000	2,000	9,588,000	312,650,000	87,475,000	3,128,000	(104,327,000)
Stock Issued During Period, Value, Stock Options Exercised	(1,121,000)		(90,000)	(90,000)			(1,121,000)
Allocated Share-based Compensation Expense	1,676,000			1,676,000
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	3,078,000		137,000	3,513,000			(572,000)
Net Loss	(15,887,000)				(15,887,000)
Foreign currency translation adjustments	915,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	915,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	774,000					774,000
Amortization of prior service costs and unrecognized (losses) gains	(169,000)
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, after Tax	(169,000)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(14,367,000)
Exchange of Convertible Notes	5,021,000			5,021,000
Payments of Ordinary Dividends, Common Stock	(414,000)
Dividends, Common Stock, Cash	(414,000)
Adoption of Credit Loss Standard	(243,000)
Total Shareholders’ Equity at Jun. 30, 2020	302,146,000	2,000	9,815,000	322,770,000	70,931,000	4,648,000	(106,020,000)
Total Shareholders’ Equity at Mar. 31, 2020	304,512,000	2,000	9,815,000	313,623,000	87,550,000	(1,377,000)	(105,101,000)
Stock Issued During Period, Value, Stock Options Exercised	(347,000)						(347,000)
Allocated Share-based Compensation Expense	1,282,000		0	1,282,000			0
Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures	2,272,000		0	2,844,000			(572,000)
Net Loss	(16,619,000)				(16,619,000)
Foreign currency translation adjustments	5,109,000
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	5,109,000
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	916,000					916,000
Amortization of prior service costs and unrecognized (losses) gains	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(10,594,000)
Exchange of Convertible Notes	5,021,000			5,021,000
Total Shareholders’ Equity at Jun. 30, 2020	$ 302,146,000	$ 2,000	$ 9,815,000	$ 322,770,000	$ 70,931,000	$ 4,648,000	$ (106,020,000)