Schedule II-Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Change in valuation and qualifying accounts
Balance at End of Year	$ 2,981	$ 2,507
Valuation Allowance on Deferred Tax Assets
Change in valuation and qualifying accounts
Balance at Beginning of Year	2,507	5,665	5,458
Additions Charged to Expense	474	169	207
Deductions		(3,327)
Balance at End of Year	2,981	2,507	5,665
Reserve for Inventory Obsolescence
Change in valuation and qualifying accounts
Balance at Beginning of Year	18,301	16,679	8,801
Additions Charged to Expense	3,431	3,341	12,136
Deductions	(11,195)	(1,719)	(4,258)
Balance at End of Year	$ 10,537	$ 18,301	$ 16,679