Segment Results - Operating Segment Information (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended			3 Months Ended																12 Months Ended						3 Months Ended																12 Months Ended						3 Months Ended																12 Months Ended						3 Months Ended								12 Months Ended						3 Months Ended								12 Months Ended						3 Months Ended												12 Months Ended									1 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012 acre	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Real Estate Leasing		Sep. 30, 2013 Real Estate Leasing		Jun. 30, 2013 Real Estate Leasing		Mar. 31, 2013 Real Estate Leasing		Dec. 31, 2012 Real Estate Leasing		Sep. 30, 2012 Real Estate Leasing		Jun. 30, 2012 Real Estate Leasing		Mar. 31, 2012 Real Estate Leasing		Dec. 31, 2013 Real Estate Leasing		Dec. 31, 2012 Real Estate Leasing		Dec. 31, 2011 Real Estate Leasing		Dec. 31, 2013 Real Estate Development and Sales		Sep. 30, 2013 Real Estate Development and Sales		Jun. 30, 2013 Real Estate Development and Sales		Mar. 31, 2013 Real Estate Development and Sales		Dec. 31, 2012 Real Estate Development and Sales		Sep. 30, 2012 Real Estate Development and Sales		Jun. 30, 2012 Real Estate Development and Sales		Mar. 31, 2012 Real Estate Development and Sales		Dec. 31, 2013 Real Estate Development and Sales		Dec. 31, 2012 Real Estate Development and Sales		Dec. 31, 2011 Real Estate Development and Sales		Dec. 31, 2013 Less amounts reported in discontinued operations		Sep. 30, 2013 Less amounts reported in discontinued operations		Jun. 30, 2013 Less amounts reported in discontinued operations		Mar. 31, 2013 Less amounts reported in discontinued operations		Dec. 31, 2012 Less amounts reported in discontinued operations		Sep. 30, 2012 Less amounts reported in discontinued operations		Jun. 30, 2012 Less amounts reported in discontinued operations		Mar. 31, 2012 Less amounts reported in discontinued operations		Dec. 31, 2013 Less amounts reported in discontinued operations		Dec. 31, 2012 Less amounts reported in discontinued operations		Dec. 31, 2011 Less amounts reported in discontinued operations		Dec. 31, 2013 Natural Materials and Construction	Sep. 30, 2013 Natural Materials and Construction	Jun. 30, 2013 Natural Materials and Construction	Mar. 31, 2013 Natural Materials and Construction	Dec. 31, 2012 Natural Materials and Construction	Sep. 30, 2012 Natural Materials and Construction	Jun. 30, 2012 Natural Materials and Construction	Mar. 31, 2012 Natural Materials and Construction	Dec. 31, 2013 Natural Materials and Construction		Dec. 31, 2012 Natural Materials and Construction		Dec. 31, 2011 Natural Materials and Construction		Dec. 31, 2013 Agribusiness	Sep. 30, 2013 Agribusiness	Jun. 30, 2013 Agribusiness	Mar. 31, 2013 Agribusiness	Dec. 31, 2012 Agribusiness	Sep. 30, 2012 Agribusiness	Jun. 30, 2012 Agribusiness	Mar. 31, 2012 Agribusiness	Dec. 31, 2013 Agribusiness		Dec. 31, 2012 Agribusiness		Dec. 31, 2011 Agribusiness		Dec. 31, 2013 Significant Reconciling Items	Sep. 30, 2013 Significant Reconciling Items	Jun. 30, 2013 Significant Reconciling Items	Mar. 31, 2013 Significant Reconciling Items	Dec. 31, 2012 Significant Reconciling Items		Sep. 30, 2012 Significant Reconciling Items		Jun. 30, 2012 Significant Reconciling Items		Mar. 31, 2012 Significant Reconciling Items		Dec. 31, 2013 Significant Reconciling Items		Dec. 31, 2012 Significant Reconciling Items		Dec. 31, 2011 Significant Reconciling Items		Dec. 31, 2013 Other	Dec. 31, 2012 Other	Dec. 31, 2011 Other	Sep. 30, 2013 Kukui'ula Village LLC	Dec. 31, 2013 Kukui'ula Village LLC Real Estate Development and Sales	Jun. 30, 2012 Bakersfield (CA) joint venture	Dec. 31, 2012 Bakersfield (CA) joint venture	Jun. 30, 2012 Bakersfield and Santa Barbara Real Estate Projects	Dec. 31, 2012 Bakersfield and Santa Barbara Real Estate Projects Real Estate Development and Sales	Dec. 31, 2011 Waiawa joint venture	Dec. 31, 2011 Waiawa joint venture Real Estate Development and Sales
Segment Reporting Information [Line Items]
Income (loss) related to joint ventures									$ 4.3	$ (4.4)	$ (1.8)																																							$ 4.2		$ (8.3)		$ (7.9)
Segment Reporting Information, Profit (Loss) [Abstract]
Revenue	204.8	64.9	62.7	32.8	82.1	83.9	63.3	32.2	365.2	261.5	235.1	30.4		27.5		26.2		26.3		24.7		24.9		25.5		25.5		110.4		100.6		99.7		358.8		47.4		1.4		15.4		5.4		8.4		7.0		11.4		423.0		32.2		59.8		291.3		45.9		8.4		23.6		8.9	[1]	9.0	[1]	9.1	[1]	18.3	[1]	369.2	[1]	45.3	[1]	81.9	[1]	54.9	0	0	0					54.9		0		0		52.0	35.9	43.5	14.7	60.9	67.9	39.9	13.6	146.1		182.3		157.5		0	0	0	0	0	[2]	(8.3)	[2]	0	[2]	0	[2]	0	[2]	(8.3)	[2]	0	[2]
Operating profit	35.2	6.2	14.4	8.9	8.5	18.4	3.3	6.7	64.7	36.9	38.2	10.7	[1]	11.2	[1]	10.6	[1]	10.9	[1]	10.2	[1]	10.2	[1]	10.5	[1]	10.7	[1]	43.4		41.6		39.3		38.1	[1],[3]	4.6	[1],[3]	(0.7)	[1],[3]	2.4	[1],[3]	1.3	[1],[3]	3.3	[1],[3]	(9.9)	[1],[3]	0.9	[1],[3]	44.4	[4]	(4.4)	[4]	15.5	[4]	12.9	[1]	11.8	[1]	3.8	[1]	8.2	[1]	4.2	[1]	4.2	[1]	4.3	[1]	8.4	[1]	36.7	[1]	21.1	[1]	38.8	[1]	2.9	0	0	0	0	0	0	0	2.9	[5]	0	[5]	0	[5]	(3.6)	2.2	8.3	3.8	1.2	9.1	7.0	3.5	10.7		20.8		22.2
Interest Expense	(7.4)	(4.2)	(3.9)	(3.6)	(3.2)	(3.6)	(4.0)	(4.1)	(19.1)	(14.9)	(17.1)
General corporate expenses	(5.9)	(3.4)	(3.7)	(4.4)	(3.4)	(3.0)	(4.0)	(4.7)	(17.4)	(15.1)	(19.9)
Acquisition costs	(0.1)	(2.0)	(1.5)	(1.0)					(4.6)	(6.8)	0
Separation cost					0	(0.7)	(4.4)	(1.7)
Income (Loss) From Continuing Operations Before Income Taxes	21.8	(3.4)	5.3	(0.1)	1.9	11.1	(9.1)	(3.8)	23.6	0.1	1.2
Income Tax Expense (benefit)	6.6	(0.6)	2.6	(0.1)	(4.3)	0.3	(2.1)	(1.5)	8.5	(7.6)	1.0
Income From Continuing Operations	15.2	(2.8)	2.7	0	6.2	10.8	(7.0)	(2.3)	15.1	7.7	0.2
Discontinued operations, net of tax	7.8	7.2	2.3	5.0	2.5	2.6	2.6	5.1	22.3	12.8	23.3
Net Income	23.0	4.4	5.0	5.0	8.7	13.4	(4.4)	2.8	37.4	20.5	23.5
Income Attributable to Noncontrolling Interest	(0.5)	0	0	0	0	0	0	0	(0.5)	0	0
Net Income Attributable to A&B	22.5	4.4	5.0	5.0	8.7	13.4	(4.4)	2.8	36.9	20.5	23.5
Earnings Per Share, Basic	$ 0.46	$ 0.10	$ 0.11	$ 0.12	$ 0.20	$ 0.31	$ (0.10)	$ 0.07	$ 0.83	$ 0.48	$ 0.55
Earnings Per Share, Diluted	$ 0.46	$ 0.10	$ 0.11	$ 0.12	$ 0.20	$ 0.31	$ (0.10)	$ 0.07	$ 0.82	$ 0.48	$ 0.55
Basic	48.6	43.1	43.1	43.0	42.9	42.6	42.4	42.4	44.4	42.6	42.4
Diluted	49.2	43.8	43.7	43.6	43.5	43.3	42.4	42.4	45.1	42.9	42.4
Segment Reporting Information, Additional Information [Abstract]
Assets	2,285.2				1,437.3				2,285.2	1,437.3	1,386.6	1,113.4								771.3								1,113.4		771.3		772.0		640.9	[6]							504.8	[6]							640.9	[6]	504.8	[6]	451.5	[6]																							358.7				0				358.7		0		0		160.0				149.9				160.0		149.9		157.8																				12.2	11.3	5.3
Total capital expenditures									505.3	54.8	59.3																	488.5	[7]	23.1	[7]	43.6	[7]																	0.1	[8]	0	[8]	5.2	[8]																															4.8		0		0										11.8	[9]	31.7	[9]	10.5	[9]																			0.1	0	0
Depreciation and amortization									41.7	35.1	34.8																	24.3	[1]	22.0	[1]	21.6	[1]																	0.2		0.2		0.2																																4.4		0		0										11.7		11.6		11.9																				1.1	1.3	1.1
Investment in various real estate joint ventures																																		335.0								319.7								335.0		319.7		290.1
Expenditures for real estate inventory																																																		150.6		37.2		13.8
Investment in joint ventures																																																		22.2		17.4		27.9
Capital before tax credits related to Port Allen solar project					21.8					21.8
Area of agricultural parcel sold						286
Impairment of real estate assets									0	5.1	0																									6.3																																																																																												6.3				9.8		6.4
Impairment and equity losses									$ 6.6	$ 4.7	$ 0																																																																																																																				$ 6.3		$ 4.7	$ 4.7	$ 9.8		$ 6.4

[1] Amounts recast to reflect discontinued operations

[2] Represents the sale of a 286-acre parcel in 2012 classified as "Gain on sale of agricultural parcel" in the consolidated statements of income, but reflected as revenue for segment reporting purposes.

[3] The Real Estate Development and Sales segment operating profit includes non-cash impairment loss on consolidation of $6.3 million in the third quarter of 2013 related to the consolidation of The Shops at Kukui'ula and non-cash impairment and equity losses of $9.8 million in the second quarter of 2012 related to the Company’s Bakersfield and Santa Barbara real estate projects.

[4] The Real Estate Development and Sales segment includes approximately $4.2 million, $(8.3) million, and ($7.9) million in equity in (loss) earnings from its various real estate joint ventures for 2013, 2012, and 2011, respectively. Included in operating profit are non-cash impairment and equity losses of $6.3 million related to the consolidation of The Shops at Kukui'ula in 2013, $9.8 million (Bakersfield joint venture and Santa Barbara real estate project) in 2012 and $6.4 million (Waiawa real estate joint venture) in 2011.

[5] Includes the results of Grace from the acquisition date of October 1, 2013 through December 31, 2013.

[6] The Real Estate Development and Sales segment includes approximately $335.0 million, $319.7 million, and $290.1 million related to its investment in various real estate joint ventures as of December 31, 2013, 2012, and 2011, respectively.

[7] Represents gross capital additions to the leasing portfolio, including gross tax-deferred property purchases, but excluding the assumption of debt, that are reflected as non-cash transactions in the Consolidated Statements of Cash Flows.

[8] Excludes expenditures for real estate developments held for sale which are classified as Cash Flows from Operating Activities within the Consolidated Statements of Cash Flows and excludes investment in joint ventures classified as Cash Flows from Investing Activities. Operating cash flows for expenditures related to real estate developments were $150.6 million, $37.2 million, and $13.8 million for 2013, 2012, and 2011, respectively. Investments in joint ventures were $22.2 million, $17.4 million, and $27.9 million in 2013, 2012, and 2011, respectively.

[9] Includes $21.8 million of capital in 2012 related to the Company’s Port Allen solar project before tax credits.