Noncontrolling Interests - Holders of Convertible Limited Partnership Units in the Operating Partnership (Details) - Noncontrolling Interest shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019 shares	Jun. 30, 2018 shares	Jun. 30, 2019 shares	Jun. 30, 2018 shares
Noncontrolling Interest [Line Items]
Percentage of ownership interest of noncontrolling interest	25.60%		25.60%
Limited partnership units (in shares)	7,900		7,900
Limited partnership units, conversion ratio	1		1
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 (in shares)	750		750
Fully converted partnership units and diluted weighted average shares outstanding (in shares)	30,800	30,000	30,800	29,900