Operating Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leases
Carrying value of operating lease equipment after depreciation	$ 60,967,000	$ 52,173,000
Accumulated depreciation	26,990,000	33,510,000
Minimum future lease rental payments due from clients
Total	42,880,000
2014	13,990,000
2015	11,150,000
2016	8,910,000
2017	5,720,000
2018	2,600,000
Thereafter	510,000
Depreciation on assets on operating lease	$ 13,055,000	$ 15,202,000	$ 18,650,000