Summary of Significant Accounting Policies (Inventories) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Obsolete Inventory Reserve
Balance at beginning of year	$ 2,680	$ 2,775	$ 2,042
Net additions charged to earnings	1,082	328	1,345
Disposals	(882)	(423)	(612)
Balance at end of year	$ 2,880	$ 2,680	$ 2,775