Acquisition (Details) (USD $) In Thousands, unless otherwise specified			6 Months Ended		0 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Contingent consideration	Feb. 22, 2013 Endeka	Feb. 22, 2013 Endeka Existing customer contracts and relationships	Feb. 22, 2013 Endeka Technology	Feb. 22, 2013 Endeka Trademark and tradename	Feb. 22, 2013 Endeka Non-compete agreement	Feb. 22, 2013 Endeka Other intangibles	Feb. 22, 2013 Endeka Identifiable intangible assets Minimum	Feb. 22, 2013 Endeka Identifiable intangible assets Maximum	Feb. 22, 2013 Endeka Contingent consideration item
Acquisition
Number of components of contingent consideration												2
Discount rate (as a percent)			50.50%							40.00%	50.00%	50.50%
Royalty rates (as a percent)										0.50%	1.50%
Estimated Fair Value
Cash paid				$ 4,894
Holdback consideration				400
Contingent consideration				1,329
Total consideration				6,623
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash				20
Other current assets				44
Property and equipment				4,617
Other assets				12
Accounts payable				(992)
Other current liabilities				(186)
Notes payable and financed liabilities				(6,476)
Deferred tax liabilities				(3,062)
Net tangible liabilities acquired				(6,023)
Intangibles					4,770	930	300	250	95
Goodwill				6,301
Total purchase price				6,623
Estimated Useful Life					10 years	6 years	10 years	2 years	10 years
Gross intangible assets	35,282	28,905
Accumulated amortization	19,222	18,311
Future amortization expense	1,054
Future amortization expense
2014	2,032
2015	1,878
2016	1,816
2017	1,651
2018	$ 1,441