Inventories: (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Raw material	$ 20,722	$ 21,867
Work in process	4,849	2,749
Finished goods	11,116	9,835
Total	$ 36,687	$ 34,451	[1]

[1] December 31, 2013 balances were derived from audited consolidated financial statements.