Per Share Information - Basic and Diluted Earnings Per Share (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amounts attributable to common stock:
Net income attributable to common stock	$ 402,044	$ 293,346	$ 314,978
Weighted average shares:
Weighted average shares outstanding for basic earnings per share attributable to common stock (in shares)	145,710	152,963	156,124
Effect of dilutive unvested non-participating stock-based awards (in shares)	1,824	1,263	1,031
Weighted average shares outstanding for diluted earnings per share attributable to common stock (in shares)	147,534	154,226	157,155