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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income attributable to CAI common stockholders	$ 17,200	$ 20,006	$ 19,149	$ 17,117	$ 36,563	$ 17,587	$ 12,638	$ 5,272	$ 73,472	$ 72,060	$ 5,997
Weighted-average shares used in per share computation - basic									19,562	19,253	19,318
Effect of dilutive securities: Stock options and restricted stock									260	354	75
Weighted-average shares used in per share computation - diluted									19,822	19,607	19,393
Basic	$ 0.90	$ 1.04	$ 0.98	$ 0.84	$ 1.86	$ 0.92	$ 0.66	$ 0.28	$ 3.76	$ 3.74	$ 0.31
Diluted	$ 0.89	$ 1.03	$ 0.97	$ 0.83	$ 1.81	$ 0.90	$ 0.65	$ 0.27	$ 3.71	$ 3.68	$ 0.31