Condensed Consolidated Statements of Equity (USD $) In Millions, unless otherwise specified	Total	A&B Share- holders' Equity	Non- controlling interest
Beginning balance at Dec. 31, 2013	$ 1,168.7	$ 1,159.8	$ 8.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	35.4	35.0	0.4
Other comprehensive income, net of tax	1.0	1.0
Dividends paid on common stock	(1.9)	(1.9)
Share-based compensation	1.2	1.2
Shares issued or repurchased, net	(1.3)	(1.3)
Excess tax benefit from share-based awards	1.2	1.2
Ending balance at Mar. 31, 2014	1,204.3	1,195.0	9.3
Beginning balance at Dec. 31, 2014	1,214.8	1,203.9	10.9
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	25.9	25.3	0.6
Other comprehensive income, net of tax	0.5	0.5
Dividends paid on common stock	(2.5)	(2.5)
Share-based compensation	1.2	1.2
Shares issued or repurchased, net	(1.1)	(1.1)
Excess tax benefit from share-based awards	0.2	0.2
Ending balance at Mar. 31, 2015	$ 1,239.0	$ 1,227.5	$ 11.5