Computer Software to be Sold (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Movement in Capitalized Computer Software, Net [Roll Forward]
Capitalized Software Development Costs, Net Period Start	$ 3,841	$ 3,123	$ 2,601
Capitalized Software Development Costs, Additions	3,908	2,609	2,244
Capitalized Software Development Costs, Amortization	(2,475)	(1,891)	(1,722)
Capitalized Software Development Costs, Net Period End	5,274	3,841	3,123
Research and Development Expense, Software (Excluding Acquired in Process Cost)	$ 1,900	$ 1,100	$ 1,400