Noncontrolling Interests - Holders of Convertible Limited Partnership Units in the Operating Partnership (Details) - Noncontrolling Interest - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.80%		25.80%
Limited partnership units	7,300		7,300
Limited partnership units, conversion ratio	100.00%		100.00%
Outstanding stock percent that should be acquired for rights to be exercised	39.90%		39.90%
Limited partnership units convertible into shares of common stock, eligible for conversion	965		965
Fully converted partnership units and diluted weighted average shares outstanding	28,500	28,100	28,400	27,900