Other Current Assets and Other Current Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Other current assets [Abstract]
Revenue recognized in excess of billings, net of reserves of $1,566 and $1,763, respectively	$ 21,639	$ 18,812
Equity investment	1,575	2,016
Other non-trade receivables	283	793
Total other current assets	23,497	21,621
Revenue recognized in excess of billings, reserves	1,566	1,763
Other current liabilities [Abstract]
Customer deposits	3,315	3,409
Acquisition obligations	2,755	2,815
Accrued taxes	1,189	998
Leases line facility	211	897
Leases payable	30	83
Other liabilities	2,017	4,404
Total other current liabilities	$ 9,517	$ 12,606