Inventories: (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw material	$ 20,912	$ 23,006
Work in process	5,126	3,546
Finished goods	11,622	10,381
Total	$ 37,660	$ 36,933	[1]

[1] December 31, 2014 balances were derived from audited consolidated financial statements.