Fair Value of Financial Instruments (Details) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes and bonds payable	[1]	$ 1,431.5	$ 1,403.7
Mortgage notes receivable	[2]	0.0	1.9
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes and bonds payable	[1]	1,443.8	1,438.8
Mortgage notes receivable	[2]	$ 0.0	$ 1.9

[1] Level 3 - Fair value derived from valuation techniques in which one of more significant inputs or significant value drivers are unobservable.

[2] Level 2 - Fair value based on quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-driven valuations in which significant inputs and significant value drivers are observable in active markets.