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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Net income attributable to CAI common stockholders used in the calculation of basic and diluted earnings per share	$ (12,582)	$ 12,989	$ 12,889	$ 13,542	$ 16,162	$ 16,395	$ 13,446	$ 14,271	$ 26,838	$ 60,274	$ 63,926
Weighted-average shares used in the calculation of basic earnings per share									20,773	20,732	22,157
Effect of dilutive securities: Stock options and restricted stock									215	423	515
Weighted-average shares used in the calculation of diluted earnings per share									20,988	21,155	22,672
Basic	$ (0.62)	$ 0.62	$ 0.61	$ 0.65	$ 0.78	$ 0.78	$ 0.61	$ 0.64	$ 1.29	$ 2.91	$ 2.89
Diluted	$ (0.62)	$ 0.62	$ 0.60	$ 0.64	$ 0.76	$ 0.77	$ 0.60	$ 0.63	$ 1.28	$ 2.85	$ 2.82