Acquisitions - Kailua Portfolio Acquisition(Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				12 Months Ended			0 Months Ended		12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 20, 2013 Kailua Portfolio Acquisition Property acre	Dec. 31, 2013 Kailua Portfolio Acquisition	Dec. 31, 2013 Kailua Portfolio Acquisition	Dec. 31, 2012 Kailua Portfolio Acquisition	Dec. 20, 2013 Bridge Loan Kailua Portfolio Acquisition	Dec. 20, 2013 Mortgages Kailua Portfolio Acquisition	Dec. 20, 2013 Ground Lease Kailua Portfolio Acquisition acre	Dec. 20, 2013 Retail Kailua Portfolio Acquisition sqft
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net [Abstract]
Property, plant and equipment								$ 367.7
Intangible assets								30.4
Total assets acquired								398.1
Intangible liabilities								26.0
Total liabilities assumed								37.4
Net assets acquired								360.7
Business Combination, Pro Forma Information [Abstract]
Operating revenue										391.0	285.5
Income from continuing operations, after tax										23.3	14.2
Net revenues since acquisition									0.8
Net earnings (loss) since acquisition									0.4
Fair value of consideration transferred								360.7
Liabilities assumed in a business combination												60.0	12.0
Number of real estate properties								43
Area of real building improvements owned by third-party															760,000
Area of properties that is subject to ground leases														51
Area of properties that are preservation-zone land								585
The purchase was funded with 1031 and 1033 proceeds								270.0
Liabilities assumed in a business combination								11.4
Acquisition related costs	$ 0.1	$ 2.0	$ 1.5	$ 1.0	$ 4.6	$ 6.8	$ 0			$ 1.1