Earnings Per Share (Reconciliation Of Basic And Diluted Net Income Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Numerator [Abstract]
Net income attributable to CAI common stockholders used in the calculation of basic and diluted earnings per share	$ 16,162	$ 16,395	$ 13,446	$ 14,271	$ 15,591	$ 15,337	$ 16,931	$ 16,067	$ 60,274	$ 63,926	$ 63,465
Denominator [Abstract]
Weighted average shares used in the calculation of basic earnings per share (in shares)									20,732	22,157	19,495
Effect of dilutive securities (in shares)									423	515	450
Weighted average shares used in the calculation of diluted earnings per share (in shares)									21,155	22,672	19,945
Net income per share attributable to CAI common stockholders [Abstract]
Basic (in dollars per share)	$ 0.78	$ 0.78	$ 0.61	$ 0.64	$ 0.70	$ 0.69	$ 0.76	$ 0.73	$ 2.91	$ 2.89	$ 3.26
Diluted (in dollars per share)	$ 0.76	$ 0.77	$ 0.60	$ 0.63	$ 0.69	$ 0.68	$ 0.75	$ 0.71	$ 2.85	$ 2.82	$ 3.18