CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
REVENUE
Rental	$ 1,057,413	$ 976,865	$ 893,457
Tenant reimbursements	43,104	42,015	37,118
Other	2,655	4,405	2,930
Total revenue	1,103,172	1,023,285	933,505
EXPENSES
Depreciation and amortization	449,943	409,215	374,661
Interest	219,974	233,079	216,366
General and administrative	51,966	49,298	51,085
Property (including reimbursable)	62,865	55,352	53,871
Income taxes	3,262	3,169	3,461
Provisions for impairment	20,664	10,560	4,126
Total expenses	808,674	760,673	703,570
Gain on sales of real estate	21,979	22,243	39,205
Income from continuing operations	316,477	284,855	269,140
Income from discontinued operations			2,800
Net income	316,477	284,855	271,940
Net income attributable to noncontrolling interests	(906)	(1,089)	(1,305)
Net income attributable to the Company	315,571	283,766	270,635
Preferred stock dividends	(27,080)	(27,080)	(37,062)
Excess of redemption value over carrying value of preferred shares redeemed			(6,015)
Net income available to common stockholders	$ 288,491	$ 256,686	$ 227,558
Amounts available to common stockholders per common share:
Income from continuing operations, basic and diluted (in dollars per share)	$ 1.13	$ 1.09	$ 1.03
Net income, basic and diluted (in dollars per share)	$ 1.13	$ 1.09	$ 1.04
Weighted average common shares outstanding:
Basic (in shares)	255,066,500	235,767,932	218,390,885
Diluted (in shares)	255,624,250	236,208,390	218,767,885