Background and Basis of Presentation (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended	0 Months Ended
Dec. 31, 2013 Segment	Dec. 31, 2012	Dec. 31, 2013 Real Estate Segment	Dec. 31, 2013 Agribusiness Segment	Oct. 02, 2013 Natural Materials and Construction Grace Pacific Corporation Segment	Dec. 31, 2012 Scenario, Adjustment
Segment Reporting Information [Line Items]
Number of shares of AB common stock received		1
Number of operating segments	4		2	1	1
Number of industries	3
Intangible assets - net	$ 74.1	$ 8.3				$ 8.3
Other assets	$ 75.9	$ 63.0				$ (8.3)

Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16212-109274

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph ((a)(1),(b))

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 142

-Paragraph 42, 45

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_IntangibleAssetsNetExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant