Noncontrolling Interests - Holders of Convertible Limited Partnership Units in the Operating Partnership (Details) - Noncontrolling Interest shares in Thousands	3 Months Ended
	Mar. 31, 2019 shares	Mar. 31, 2018 shares
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.60%
Limited partnership units (in shares)	7,800
Limited partnership units, conversion ratio	1
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 (in shares)	900
Fully converted partnership units and diluted weighted average shares outstanding (in shares)	30,700	29,800