Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016		Dec. 31, 2015	[2]	Dec. 31, 2014	[2]
Selected Quarterly Financial Data [Abstract]
Revenue	$ 77,274		$ 78,472		$ 71,642		$ 66,966		$ 65,692		$ 66,117		$ 59,366		$ 58,492		$ 294,354	[2]	$ 249,667		$ 227,589	[3]
Operating expenses	64,664		71,110		56,784		48,510		68,292		42,861		36,232		34,842		241,068	[2]	182,227		124,035	[3]
Operating (loss) income	12,610		7,362		14,858		18,456		(2,600)		23,256		23,134		23,650		53,286	[2]	67,440		103,554	[3]
Net (loss) income attributable to CAI common stockholders	$ 620		$ (5,451)		$ 3,711		$ 7,117		$ (12,630)		$ 12,934		$ 12,824		$ 13,473		$ 5,997		$ 26,601		$ 59,887
Net (loss) income per basic share attributable to CAI common stockholders	$ 0.03		$ (0.29)		$ 0.20		$ 0.37		$ (0.63)		$ 0.62		$ 0.61		$ 0.64		$ 0.31		$ 1.28		$ 2.89
Net (loss) income per diluted share attributable to CAI common stockholders	$ 0.03		$ (0.29)		$ 0.20		$ 0.37		$ (0.63)		$ 0.61		$ 0.60		$ 0.63		$ 0.31		$ 1.27		$ 2.83

[1] Amounts for the quarters ended March 31, 2016 and 2015, June 30, 2016 and 2015, September 30, 2016 and 2015, and December 31, 2015 have been restated for immaterial corrections of identified errors relating to prepaid loan fees (see Note 2 (b) "Correction of Immaterial Errors")

[2] Amounts for the years ended December 31, 2015 and 2014 have been restated for immaterial corrections of identified errors relating to prepaid loan fees (see Note 2 (b) "Correction of Immaterial Errors").

[3] At the inception of the lease, the Company records the total minimum lease payments, executory costs, if any, and unguaranteed residual value as gross finance lease receivables. The gross finance lease receivables are reduced as customer payments are received. There was $2.1 million and no unguaranteed residual value, respectively, at December 31, 2016 and 2015, included in gross finance lease receivables. There were no executory costs included in gross finance lease receivables as of December 31, 2016 and 2015.