Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
OPERATING ACTIVITIES
Net income	$ 60,243	$ 33,134
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	105,148	93,668
Other amortization	3,056	2,477
Stock-based compensation	7,496	5,649
Amortization of straight-line rent receivable	(4,867)	(5,446)
Amortization of straight-line rent liability	492	(93)
Gain on sales of real estate assets	(39,525)	(8)
Impairment of real estate assets	5,387
Provision for bad debts, net	175	(8)
Changes in operating assets and liabilities:
Other assets	(6,037)	(1,436)
Accounts payable and accrued liabilities	(3,301)	(3,889)
Other liabilities	1,098	(21,628)
Net cash provided by operating activities	129,365	102,420
INVESTING ACTIVITIES
Acquisitions of real estate	(72,934)	(162,702)
Development of real estate	(11,753)	(28,508)
Additional long-lived assets	(52,305)	(49,794)
Proceeds from sales of real estate	119,425
Proceeds from mortgages and notes receivable repayments	15	14
Net cash used in investing activities	(17,552)	(240,990)
FINANCING ACTIVITIES
Net repayments on unsecured credit facility	(107,000)	(125,000)
Repayment on term loan		(50,000)
Borrowings of notes and bonds payable		11,500
Repayments on notes and bonds payable	(4,654)	(36,786)
Dividends paid	(104,860)	(96,998)
Net proceeds from issuance of common stock	248,384	450,304
Common stock redemptions	(1,125)	(1,282)
Debt issuance and assumption costs	(84)	(4,621)
Net cash provided by financing activities	30,661	147,117
Increase in cash, cash equivalents and restricted cash	142,474	8,547
Cash, cash equivalents and restricted cash at beginning of period	54,507	4,102
Cash, cash equivalents and restricted cash at beginning of period	196,981	12,649
Supplemental Cash Flow Information:
Interest paid	42,136	43,879
Invoices accrued for construction, tenant improvements and other capitalized costs	6,842	10,014
Mortgage notes payable assumed upon acquisition (adjusted to fair value)	12,460	13,951
Capitalized interest	$ 681	$ 828