Related Party Transactions (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($) commercial_unit	Dec. 31, 2018 USD ($)
The Collection High-rise Residential Condominium \| Hawaii
Related Party Transaction [Line Items]
Number of units acquired \| commercial_unit		5
Payments to acquire real estate		$ 6.9
Affiliated Entity \| Materials & Construction \| Supplier Contracts
Related Party Transaction [Line Items]
Revenue from related parties	$ 7.4	10.5	$ 16.6
Receivables from related parties	0.9	0.2
Payables to related parties	0.3	1.2
Affiliated Entity \| Real estate leasing and development \| Lease Agreements
Related Party Transaction [Line Items]
Revenue from related parties		1.3	4.3
Expenses related to affiliates	1.1	0.1	0.1
Affiliated Entity \| Land Operations \| Land Operations
Related Party Transaction [Line Items]
Revenue from related parties	3.1	2.2	$ 1.1
Affiliated Entity \| Land Operations \| Service Revenues and Interest
Related Party Transaction [Line Items]
Receivables from related parties	0.1	0.1
Affiliated Entity \| Land Operations \| Extension of Secured Note Receivable
Related Party Transaction [Line Items]
Receivable from affiliate	$ 9.5	$ 13.1

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