Identifiable intangible assets (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Software costs capitalized	$ 942,000	$ 2,362,000	$ 1,622,000	$ 5,096,000
Amortization of capitalized software costs	398,000	128,000	764,000	282,000
Amortization of identifiable intangible assets	150,000	205,000	303,000	410,000
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	26,831,000		26,831,000		25,211,000
Less accumulated amortization	(10,387,000)		(10,387,000)		(9,323,000)
Intangible assets - net	16,444,000		16,444,000		15,888,000
Future amortization of intangible assets assuming straight-line amortization of capitalized software costs [Abstract]
2012	1,176,000		1,176,000
2013	2,483,000		2,483,000
2014	2,459,000		2,459,000
2015	2,167,000		2,167,000
2016	2,165,000		2,165,000
Thereafter	3,894,000		3,894,000
Total	14,344,000		14,344,000
Acquired and internally developed software costs [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	19,522,000		19,522,000		17,902,000
Customer relationships [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	4,519,000		4,519,000		4,519,000
Trademarks (non-amortizable) [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	2,100,000		2,100,000		2,100,000
Other [Member]
Components of identifiable intangible assets [Abstract]
Intangible assets - gross	$ 690,000		$ 690,000		$ 690,000
Minimum [Member]
Finite-Lived Intangible Assets [Line Items]
Remaining estimated economic life of the product			3 years
Maximum [Member]
Finite-Lived Intangible Assets [Line Items]
Remaining estimated economic life of the product			7 years