Selected Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 103,420	$ 105,805	[1]	$ 104,088	[1]	$ 103,227	$ 106,846	$ 106,693	$ 96,586	$ 86,270	$ 416,540	$ 396,395	$ 315,917
Operating expenses	71,934	70,031	[1]	71,436	[1]	68,455	68,216	67,044	60,065	54,161	281,856	249,486	217,466
Operating (loss) income	31,486	35,774	[1]	32,652	[1]	34,772	38,630	39,649	36,521	32,109	134,684	146,909	98,451
Net income from continuing operations	$ 9,541	$ 11,926	[1]	$ 8,487	[1]	$ 12,238	$ 16,084	$ 20,571	$ 19,503	$ 17,823	$ 42,192	$ 73,981	$ 62,565
Net (loss) income per basic share attributable to CAI common stockholders	$ 0.54	$ 0.69	[1]	$ 0.48	[1]	$ 0.66	$ 0.85	$ 1.07	$ 1.00	$ 0.87	$ 1.25	$ 3.76	$ 3.74
Net (loss) income per diluted share attributable to CAI common stockholders	$ 0.54	$ 0.68	[1]	$ 0.47	[1]	$ 0.65	$ 0.83	$ 1.06	$ 0.99	$ 0.86	$ 1.23	$ 3.71	$ 3.68
Previously Reported [Member]
Revenue		$ 107,570		$ 105,576
Operating expenses		70,750		69,566
Operating (loss) income		36,820		36,010
Net income from continuing operations		$ 12,958		$ 12,328
Net (loss) income per basic share attributable to CAI common stockholders		$ 0.75		$ 0.70
Net (loss) income per diluted share attributable to CAI common stockholders		$ 0.74		$ 0.69
Reclassification [Member]
Revenue		$ (1,765)		$ (1,488)
Operating expenses		(719)		1,870
Operating (loss) income		(1,046)		(3,358)
Net income from continuing operations		$ (1,032)		$ (3,841)
Net (loss) income per basic share attributable to CAI common stockholders		$ (0.06)		$ (0.22)
Net (loss) income per diluted share attributable to CAI common stockholders		$ (0.06)		$ (0.22)

[1] Subsequent to the filing of the Company's Quarterly Reports on Form 10-Q for the periods ended June 30, 2019 and September 30, 2019, the Company identified misstatements arising from the misclassification of certain leases. The Company has determined that the misstatements are immaterial to the prior quarters' consolidated financial statements. The impact of the adjustments is set out below (in thousands, except share amount):