Inventories: (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Inventory Disclosure [Abstract]
Raw material	$ 18,704	$ 20,808
Work in process	4,134	3,013
Finished goods	11,315	12,512
Total	$ 34,153	$ 36,333	[1]

[1] December 31, 2012 balances were derived from audited consolidated financial statements.