Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
OPERATING ACTIVITIES
Net income	$ 50,778	$ 14,127
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	90,000	86,349
Stock-based compensation	4,558	3,400
Straight-line rent receivable	(7,671)	(7,907)
Straight-line rent liability	583	522
Gain on sales of real estate assets	(58,092)	(3)
Loss on extinguishment of debt	27,998
Impairments of real estate assets	3,638	11,034
Pension termination	5,260	0
Impairment of internally-developed software	654	0
Provision for bad debts, net	(203)	126
Changes in operating assets and liabilities:
Other assets	(2,502)	(16,231)
Accounts payable and accrued liabilities	(2,285)	(10,644)
Other liabilities	594	(3,123)
Net cash provided by operating activities	113,310	77,650
INVESTING ACTIVITIES
Acquisitions of real estate	(70,043)	(37,694)
Development of real estate	(10,165)
Acquisition of additional long-lived assets	(35,709)	(54,899)
Funding of mortgages and notes receivable		(1,244)
Proceeds from acquisition of real estate upon mortgage note receivable default		204
Proceeds from sales of real estate	134,432	6,134
Proceeds from mortgages and notes receivable repayments	1,914	5,618
Net cash provided by (used in) investing activities	20,429	(81,881)
FINANCING ACTIVITIES
Net borrowings (repayments) on unsecured credit facility	57,000	(154,000)
Borrowings on term loan		200,000
Borrowings on notes and bonds payable	249,793
Repayments on notes and bonds payable	(49,632)	(4,415)
Redemption of notes and bonds payable	(333,222)
Dividends paid	(90,078)	(86,923)
Net proceeds from issuance of common stock	41,757	52,712
Common stock redemptions	(271)	(382)
Settlement of swaps	(1,684)
Distributions to noncontrolling interest holders		(380)
Purchase of noncontrolling interest		(8,189)
Debt issuance and assumption costs	(2,424)	(1,179)
Net cash used in financing activities	(128,761)	(2,756)
Increase (decrease) in cash and cash equivalents	4,978	(6,987)
Cash and cash equivalents, beginning of period	3,519	8,671
Cash and cash equivalents, end of period	8,497	1,684
Supplemental Cash Flow Information:
Interest paid	55,995	59,227
Company-financed real estate property sales		1,900
Invoices accrued for construction, tenant improvement and other capitalized costs	8,924	4,662
Mortgage notes payable assumed upon acquisition (adjusted to fair value)	19,431	$ 12,618
Capitalized interest	$ 113