Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Numerator for basic and diluted earnings per share:
Income from continuing operations	$ 63,302	$ 103,281	$ 169,300	$ 80,108	$ 393,820	$ 615,210	$ 152,991	$ 199,201	$ 415,991	$ 1,361,222	$ 652,412
Discontinued operations	0	0	0	(10)	(15)	(19)	(23)	(53)	(10)	(110)	(922)
Net income	63,302	103,281	169,300	80,098	393,805	615,191	152,968	199,148	415,981	1,361,112	651,490
Comprehensive income attributable to noncontrolling interests	1,029	1,309	2,781	1,395	1,251	1,233	1,137	1,021	6,514	4,642	2,259
Net income attributable to noncontrolling interests									6,514	4,642	2,259
Net income attributable to common stockholders	$ 62,273	$ 101,972	$ 166,519	$ 78,703	$ 392,554	$ 613,958	$ 151,831	$ 198,127	$ 409,467	$ 1,356,470	$ 649,231
Denominator for basic earnings per share—weighted average shares
Denominator for basic earnings per share - weighted average shares (in shares)									356,265	355,326	344,703
Stock options (in shares)									174	494	569
Restricted stock awards (in shares)									331	265	176
OP unitholder interests (in shares)									2,531	2,481	2,942
Denominator for diluted earnings per share - adjusted weighted average shares (in shares)									359,301	358,566	348,390
Basic earnings per share:
Income from continuing operations (USD per share)	$ 0.18	$ 0.29	$ 0.48	$ 0.22	$ 1.11	$ 1.73	$ 0.43	$ 0.56	$ 1.17	$ 3.83	$ 1.89
Net income attributable to common stockholders (USD per share)	0.17	0.29	0.47	0.22	1.10	1.72	0.43	0.56	1.15	3.82	1.88
Diluted earnings per share:
Income from continuing operations (USD per share)	0.18	0.29	0.47	0.22	1.10	1.71	0.43	0.56	1.16	3.80	1.87
Net income attributable to common stockholders (USD per share)	$ 0.17	$ 0.28	$ 0.46	$ 0.22	$ 1.09	$ 1.71	$ 0.42	$ 0.55	$ 1.14	$ 3.78	$ 1.86
Anti-dilutive options outstanding (in shares)									3,500	3,000	1,400