Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments and Contingencies [Abstract]
Maximum lease term	8 years
Future minimum lease payments required for office facilities and equipment [Abstract]
2013	$ 1,416,000
2014	1,285,000
2015	1,102,000
2016	1,063,000
2017 and thereafter	871,000
Future minimum lease payments under operating lease agreements	5,737,000
Office facility expense	1,400,000	1,300,000	1,200,000
Outstanding letter of credit	100,000	100,000
Rental equipment payable	2,561,000	13,301,000
Commitments to purchase container equipment	$ 24,800,000