Changes in Equity (Schedule of Stockholders Equity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	$ 1,430,525	$ 1,787,889
Net income	26,138	4,722
Other comprehensive income (loss)	(3,048)	1,351
Share-based compensation	3,507	4,783
Issuance of common stock, net	(694)	(2,364)
Contributions from noncontrolling interests		2,798
Distributions to noncontrolling interests	(13,500)	(4,000)
Balance	1,442,928	1,795,179
Common Stock [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	50,279	50,026
Issuance of common stock, net	298	154
Balance	50,577	50,180
Additional Paid-In Capital [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	1,117,972	1,102,919
Share-based compensation	3,507	4,783
Issuance of common stock, net	(992)	(2,518)
Balance	1,120,487	1,105,184
Retained Earnings [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	313,991	701,681
Net income	17,371	(356)
Balance	331,362	701,325
Accumulated Other Comprehensive Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(42,100)	(45,449)
Other comprehensive income (loss)	(1,028)	1,249
Balance	(43,128)	(44,200)
Noncontrolling Interests [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance	(9,617)	(21,288)
Net income	8,767	5,078
Other comprehensive income (loss)	(2,020)	102
Contributions from noncontrolling interests		2,798
Distributions to noncontrolling interests	(13,500)	(4,000)
Balance	$ (16,370)	$ (17,310)