Business Segments - (Information by Segment) (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 232,913,000	$ 235,774,000	$ 235,858,000	$ 223,419,000	$ 244,576,000	$ 244,559,000	$ 246,152,000	$ 237,060,000	$ 927,964,000	$ 972,347,000	$ 966,497,000
Charges	8,188,000	$ 1,628,000	1,321,000	692,000	1,816,000	920,000	344,000	$ 401,000	11,829,000	3,481,000	12,274,000
Depreciation and amortization									15,563,000	15,556,000	14,631,000
Net interest expense (income)									28,647,000	27,802,000	22,434,000
Operating Income (Loss)									(10,410,000)	(18,294,000)	(40,159,000)
Restructuring Charges, Net of Inventory Adjustments									(11,829,000)	(3,481,000)	(12,274,000)
Asset write-downs to intangible assets									(587,000)	(583,000)	(320,000)
Loss (gain) on Convertible Debt Derivatives			$ (1,470,000)	$ 273,000	(7,790,000)	$ (4,080,000)	$ (21,000)		1,197,000	11,994,000	(3,657,000)
Gain (Loss) on Extinguishment of Debt	(5,885,000)								(6,165,000)	0	0
Interest Revenue (Expense), Net									(28,647,000)	(27,802,000)	(22,434,000)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									(44,025,000)	(34,102,000)	(66,250,000)
Assets	852,126,000				885,855,000				852,126,000	885,855,000	1,066,033,000
Long-lived assets	496,249,000				488,445,000				496,249,000	488,445,000	609,119,000
Expenditures for assets									10,874,000	9,823,000	14,569,000
Europe
Segment Reporting Information [Line Items]
Revenues									533,048,000	558,518,000	535,326,000
Charges									9,579,000	1,773,000	1,975,000
Depreciation and amortization									7,851,000	8,125,000	7,446,000
Net interest expense (income)									368,000	225,000	229,000
Operating Income (Loss)									36,174,000	32,673,000	33,160,000
Assets	602,471,000				611,230,000				602,471,000	611,230,000	646,085,000
Long-lived assets	408,847,000				407,021,000				408,847,000	407,021,000	430,998,000
Expenditures for assets									6,041,000	5,348,000	5,819,000
North America
Segment Reporting Information [Line Items]
Revenues									348,201,000	364,590,000	380,290,000
Charges									1,617,000	1,359,000	8,889,000
Depreciation and amortization									6,429,000	6,228,000	5,745,000
Net interest expense (income)									28,070,000	27,355,000	22,006,000
Operating Income (Loss)									(7,592,000)	(32,506,000)	(36,992,000)
Assets	212,733,000				242,341,000				212,733,000	242,341,000	388,021,000
Long-lived assets	79,369,000				77,009,000				79,369,000	77,009,000	173,578,000
Expenditures for assets									3,679,000	3,648,000	7,755,000
Other Segments
Segment Reporting Information [Line Items]
Revenues									46,715,000	49,239,000	50,881,000
Charges									633,000	349,000	1,410,000
Depreciation and amortization									1,283,000	1,203,000	1,440,000
Net interest expense (income)									209,000	222,000	199,000
Operating Income (Loss)									(26,576,000)	(14,397,000)	(23,733,000)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest									853,000	2,462,000
Assets	36,922,000				32,284,000				36,922,000	32,284,000	31,927,000
Long-lived assets	$ 8,033,000				$ 4,415,000				8,033,000	4,415,000	4,543,000
Expenditures for assets									1,154,000	827,000	995,000
Operating Segments | Europe
Segment Reporting Information [Line Items]
Revenues									533,048,000	558,518,000	535,326,000
Operating Segments | North America
Segment Reporting Information [Line Items]
Revenues									348,201,000	364,590,000	380,290,000
Operating Segments | Other Segments
Segment Reporting Information [Line Items]
Revenues									46,715,000	49,239,000	50,881,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Revenues									107,945,000	124,465,000	113,926,000
Intersegment Eliminations | Europe
Segment Reporting Information [Line Items]
Revenues									14,185,000	15,784,000	13,815,000
Intersegment Eliminations | North America
Segment Reporting Information [Line Items]
Revenues									80,727,000	90,944,000	84,799,000
Intersegment Eliminations | Other Segments
Segment Reporting Information [Line Items]
Revenues									$ 13,033,000	$ 17,737,000	$ 15,312,000