Segment Results (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 Segment	Dec. 31, 2013	Dec. 31, 2012
Revenue, Major Customer [Line Items]
Number of operating segments									4
Revenue	$ 165.1	$ 153.4	$ 146.7	$ 94.8	$ 204.8	$ 64.9	$ 62.7	$ 32.8	$ 560.0	$ 365.2	$ 261.5
Customer Concentration Risk | C&H Sugar Company, Inc
Revenue, Major Customer [Line Items]
Revenue									$ 65.5	$ 87.6	$ 117.5
Buildings | Real Estate Segment
Revenue, Major Customer [Line Items]
Number of real estate properties	60								60
Net rentable area	5,100,000								5,100,000
Oahu | Land | Real Estate Segment
Revenue, Major Customer [Line Items]
Area of real estate property	51								51
Oahu | Commercial Real Estate | Real Estate Segment
Revenue, Major Customer [Line Items]
Area of real estate property	760,000								760,000
Neighbor Islands | Land | Real Estate Segment
Revenue, Major Customer [Line Items]
Area of real estate property	64								64