Debt and Capital Lease Obligations (Details) (USD $)	12 Months Ended		12 Months Ended		12 Months Ended				12 Months Ended		12 Months Ended		12 Months Ended					12 Months Ended		3 Months Ended	12 Months Ended				12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Revolving Credit Facility [Member]	Dec. 31, 2011 Revolving Credit Facility [Member]	Dec. 31, 2012 Revolving Credit Facility [Member] CAI Rail Inc [Member]	Dec. 31, 2011 Revolving Credit Facility [Member] CAI Rail Inc [Member]	Dec. 31, 2012 Revolving Credit Facility [Member] CAI Rail Inc [Member] Minimum [Member]	Dec. 31, 2012 Revolving Credit Facility [Member] CAI Rail Inc [Member] Maximum [Member]	Dec. 31, 2012 Term Loan [Member] Development Bank of Japan [Member]	Dec. 31, 2011 Term Loan [Member] Development Bank of Japan [Member]	Dec. 31, 2012 Term Loan [Member] Consortium of Banks [Member]	Dec. 31, 2011 Term Loan [Member] Consortium of Banks [Member]	Dec. 31, 2012 Term Loan [Member] Consortium of Banks, Note Dated April 11, 2012 [Member]	Apr. 11, 2012 Term Loan [Member] Consortium of Banks, Note Dated April 11, 2012 [Member]	Dec. 31, 2011 Term Loan [Member] Consortium of Banks, Note Dated April 11, 2012 [Member]	Dec. 31, 2012 Term Loan [Member] Federal Funds Rate [Member] Consortium of Banks [Member]	Dec. 31, 2012 Term Loan [Member] Eurodollar Rate [Member] Consortium of Banks [Member]	Dec. 31, 2012 Senior Secured Notes [Member]	Dec. 31, 2011 Senior Secured Notes [Member]	Mar. 31, 2012 Asset Backed Warehouse Facility [Member]	Dec. 31, 2012 Asset Backed Warehouse Facility [Member]	Dec. 31, 2011 Asset Backed Warehouse Facility [Member]	Dec. 31, 2012 Asset Backed Notes [Member]	Dec. 31, 2011 Asset Backed Notes [Member]	Dec. 31, 2012 Collateralized Financing Obligations [Member]	Dec. 31, 2011 Collateralized Financing Obligations [Member]	Dec. 31, 2012 Swing Line Loans [Member]	Dec. 31, 2012 Standby Letters of Credit [Member]	Dec. 31, 2012 Letter of Credit [Member]
Debt [Abstract]
Current Outstanding	$ 61,044,000	$ 25,764,000	$ 0	$ 0	$ 0	$ 0			$ 800,000	$ 800,000	$ 24,964,000	$ 24,964,000	$ 9,940,000		$ 0			$ 8,240,000	$ 0		$ 0	$ 0	$ 17,100,000	$ 0	$ 0	$ 0
Long-term Outstanding	888,990,000	575,014,000	160,000,000	261,000,000	41,469,000	0			6,600,000	7,400,000	230,651,000	255,614,000	129,260,000		0			94,760,000	0		0	51,000,000	151,050,000	0	75,200,000	0
Average Interest (in hundredths)			3.00%	3.00%	2.50%	0.00%			2.70%	2.80%	3.30%	3.50%	2.50%		0.00%			4.90%	0.00%		0.00%	2.70%	3.47%	0.00%	1.10%	0.00%
Agreement Terminates			Sep. 30, 2014		Jun. 30, 2015				Jul. 31, 2014		Dec. 20, 2016		Apr. 11, 2017					Sep. 13, 2022			Sep. 30, 2023		Oct. 31, 2027		Nov. 30, 2016
Maximum credit commitment			575,000,000		85,000,000						300,000,000		142,000,000	60,000,000							100,000,000						10,000,000	15,000,000
Maximum amount credit facility might be increased			675,000,000										200,000,000
Percentage of aggregate principal to prepay, minimum (in hundredths)																		10.00%
Proceeds used to repay credit facility																		100,000,000
Proceeds used for working capital purposes																		3,000,000
Principal amount of loan									10,000,000														171,000,000
Proceeds from facility											185,000,000									49,000,000		51,000,000
Revolving Credit Facility [Abstract]
Number of business days short term borrowings payable, Maximum																											10 days
Availability borrowing capacity			414,900,000		43,500,000
Letters of credit outstanding	100,000	100,000																											100,000
Variable interest rate (in hundredths)							1.50%	2.25%
Term Loans [Abstract]
Term of loan									5 years				5 years
Number of quarterly installments									19		23
Quarterly payments of principal									200,000		3,700,000
Debt instrument final payment									6,200,000		99,900,000
Amount outstanding under the facility									7,400,000
Amortization term of facility											6 years
Periodic payments to drawn amount (in hundredths)											2.00%
Debt instrument final payment to drawn amount (in hundredths)											54.00%
Numerator for calculation of quarterly payments of principal (in hundredths)											46.00%
Terms											The Base Rate is defined as the highest of (i) the federal funds rate plus 1/2 of 1.0%, (ii) the prime rate (as published in The Wall Street Journal)
Basis spread on variable rate (in hundredths)													2.25%			0.50%	1.00%
Periodic payments specified as percentage of drawn amount (in hundredths)													1.75%
Long term debt maturity [Abstract]
2013									995,000		33,225,000		13,317,000					13,186,000					22,663,000		0
2014									6,732,000		32,387,000		13,070,000					12,782,000					22,069,000		0
2015											31,549,000		12,822,000					12,379,000					21,476,000		67,085,000
2016											186,488,000		12,581,000					10,910,000					20,883,000		10,736,000
2017													100,661,000
2017 and thereafter																		87,070,000					109,990,000
Long term debt including interest									7,727,000		283,649,000		152,451,000					136,327,000					197,081,000		77,821,000
Less: Amount representing interest									(327,000)		(28,035,000)		(13,251,000)					(33,327,000)					(28,931,000)		(2,621,000)
Long-term debt	888,990,000	575,014,000							7,400,000		255,614,000		139,200,000					103,000,000					168,150,000		75,200,000	10,000,000
Capital Lease Obligations [Abstract]
Average fixed and floating interest rates (in hundredths)	2.60%
Maturity date range start	Oct. 31, 2012
Maturity date range end	Jun. 30, 2019
Estimated future principal and interest payments under capital lease obligations [Abstract]
2013	2,401,000
2014	1,901,000
2015	1,457,000
2016	875,000
2017 and thereafter	1,090,000
Capital lease obligation including interest	7,724,000
Less: Amount representing interest	(398,000)
Capital lease obligation	$ 7,326,000