Earnings per Share and Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income per common unit - diluted
Weighted Average Limited Partnership Units Outstanding, Basic		349,902
Parent Company [Member]
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 90,446	$ 52,660
Weighted average common units outstanding for basic EPU (in shares)	167,440,000	170,704,000
Weighted average common units outstanding for diluted EPU (in shares)	167,717,000	170,959,000
Income per common share/unit - basic:
Continuing operations (in dollars per share)	$ 0.54	$ 0.31
Income per common share/unit - diluted:
Continuing operations (in dollars per share)	$ 0.54	$ 0.31
Partnership Interest [Member]
Earnings Per Share [Abstract]
Weighted average common units outstanding for basic EPU (in shares)	167,790,000	171,054,000
Weighted average common units outstanding for diluted EPU (in shares)	168,067,000	171,309,000
Income per common unit - basic
Continuing operations (in dollars per share)	$ 0.54	$ 0.31
Income per common unit - diluted
Continuing operations (in dollars per share)	$ 0.54	$ 0.31
Continuing Operations [Member] | Parent Company [Member]
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 90,446	$ 52,660
Net income for common stock unit/holders - diluted	90,446	52,660
Continuing Operations [Member] | Partnership Interest [Member]
Earnings Per Share [Abstract]
Net income attributable to common stockholders	90,636	52,771
Net income for common stock unit/holders - diluted	$ 90,636	$ 52,771