Description of Business: (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended					0 Months Ended		3 Months Ended
	Mar. 31, 2013 item	Mar. 31, 2012	Mar. 31, 2012 Other Comprehensive (Loss)	Mar. 31, 2012 Comprehensive Income	Mar. 31, 2013 SSAT Ocean Transportation item	Jun. 08, 2012 Alexander & Baldwin	Dec. 01, 2011 Alexander & Baldwin item	Mar. 31, 2013 Alexander & Baldwin	Jun. 29, 2012 Alexander & Baldwin
Description of Business
Number of vessels owned	20
Number of vessels held for sale	2
Ownership interest in SSAT (as a percent)					35.00%
Number of terminal facilities on which SSAT provides terminal and stevedoring services to Matnav and numerous international carriers					6
Number of publicly traded companies to be created after separation							2
Jones Act requirement to maintain status as U.S. citizen, maximum ownership interest permitted by non-U.S. citizens (as a percent)								22.00%
Number of shares of common stock of A&B received for each share upon separation									1
Maximum period during which services are to be provided under Transition Services Agreement						24 months
Prior Period Adjustment
Other comprehensive income	$ 1.3	$ 1.7	$ (1.7)
Comprehensive Income	$ 10.4	$ 5.5		$ 2.1