Noncontrolling Interests - Holders of Convertible Limited Partnership Units in the Operating Partnership (Details) - Noncontrolling Interest - shares shares in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.80%
Limited partnership units	7.3
Limited partnership units, conversion ratio	100.00%
Outstanding stock percent that should be acquired for rights to be exercised	39.90%
Limited partnership units convertible into shares of common stock, eligible for conversion	1.0
Fully converted partnership units and diluted weighted average shares outstanding	28.7	28.3