Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss)	$ (19,297,000)	$ (19,010,000)
Other Comprehensive Income (Loss)	(287,000)	14,328,000	$ (10,282,000)
Significant Amount Reclassified Out of AOCI	0
Foreign Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss)	(16,642,000)	(19,441,000)	(31,538,000)
Other Comprehensive Loss Before Reclassifications	2,799,000	12,097,000
Tax Effects	0	0
Other Comprehensive Income (Loss)	2,799,000	12,097,000
Other [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss)	(2,655,000)	431,000	(1,800,000)
Other Comprehensive Loss Before Reclassifications	(3,728,000)	2,901,000
Tax Effects	642,000	(670,000)
Other Comprehensive Income (Loss)	(3,086,000)	2,231,000
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss)	(19,297,000)	(19,010,000)	(33,338,000)
Other Comprehensive Loss Before Reclassifications	(929,000)	14,998,000
Tax Effects	642,000	(670,000)
Other Comprehensive Income (Loss)	$ (287,000)	$ 14,328,000	$ (10,282,000)