Segment Information (Revenue and Long-term Assets by Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Geographical [Line Items]
Inventory, Gross	$ 82,684		$ 82,684		$ 80,987
Total sales	$ 61,404	$ 59,919	$ 198,213	$ 191,341
Total sales, % Inc/Decr	2.50%		3.60%
Domestic [Member]
Geographical [Line Items]
Long-Lived Assets, Gross	$ 183,560		$ 183,560		167,326
Accumulated Amortization and Depreciation Long Lived Assets	(93,221)		(93,221)		(89,445)
long lived assets, net	90,339		90,339		77,881
Inventory, Gross	48,373		48,373		47,538
Total sales	$ 43,289	42,242	$ 136,644	131,427
Total sales, % Inc/Decr	2.50%		4.00%
International [Member]
Geographical [Line Items]
Long-Lived Assets, Gross	$ 69,532		$ 69,532		63,805
Accumulated Amortization and Depreciation Long Lived Assets	(29,680)		(29,680)		(23,980)
long lived assets, net	39,852		39,852		39,825
Inventory, Gross	34,311		34,311		$ 33,449
Total sales	$ 18,115	$ 17,677	$ 61,569	$ 59,914
Total sales, % Inc/Decr	2.50%		2.80%