Earnings Per Share (Reconciliation Of Basic And Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Earnings Per Share [Abstract]
Net income (loss) attributable to CAI common stockholders used in the calculation of basic and diluted earnings per share	$ 36,563	$ 17,587	$ 12,638	$ 5,272	$ 620	$ (5,451)	$ 3,711	$ 7,117	$ 72,060	$ 5,997	$ 26,601
Weighted-average shares used in the calculation of basic earnings per share									19,253	19,318	20,773
Effect of dilutive securities: Stock options and restricted stock									354	75	215
Weighted-average shares used in the calculation of diluted earnings per share									19,607	19,393	20,988
Basic	$ 1.86	$ 0.92	$ 0.66	$ 0.28	$ 0.03	$ (0.28)	$ 0.19	$ 0.36	$ 3.74	$ 0.31	$ 1.28
Diluted	$ 1.81	$ 0.90	$ 0.65	$ 0.27	$ 0.03	$ (0.28)	$ 0.19	$ 0.36	$ 3.68	$ 0.31	$ 1.27