SEGMENT INFORMATION (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Revenues:
Total revenues	$ 741,470	$ 682,909
Net real estate property:
Total net real estate property	18,096,467		18,075,586
United States
Revenues:
Total revenues	720,107	659,529
Net real estate property:
Total net real estate property	17,556,584		17,705,962
Canada
Revenues:
Total revenues	21,218	23,380
Net real estate property:
Total net real estate property	356,580		369,624
UNITED KINGDOM
Revenues:
Total revenues	145	0
Net real estate property:
Total net real estate property	$ 183,303		$ 0