Consolidated Statements Of Cash Flows - USD ($)	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 111,528,000	$ 95,528,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	43,668,000	39,502,000
Amortization	2,663,000	2,589,000
Straight-line rental income	(16,583,000)	(18,492,000)
Non-cash interest income on construction loan	668,000	0
Non-cash write-off of straight-line rent receivable	15,856,000	0
Gain on sale of real estate	(4,582,000)	(1,126,000)
Gain on sale of equity-method investee	(1,657,000)	0
Gain on sale of marketable securities	(23,498,000)	(61,000)
Loan recovery	0	(491,000)
Share-based compensation	1,481,000	1,930,000
Amortization of commitment fees	(303,000)	0
Loss from equity-method investee	1,214,000	765,000
Change in operating assets and liabilities:
Equity-method investment and other assets	34,000	(693,000)
Accounts payable and accrued expenses	1,637,000	(56,000)
Deferred income	(1,474,000)	1,401,000
Net cash provided by operating activities	129,316,000	120,796,000
Cash flows from investing activities:
Investment in mortgage and other notes receivable	(75,522,000)	(73,092,000)
Collection of mortgage and other notes receivable	16,461,000	19,128,000
Investment in real estate	(288,965,000)	(104,066,000)
Investment in real estate development	(24,499,000)	(8,807,000)
Investment in renovations of existing real estate	(913,000)	(2,757,000)
Payment allocated to lease purchase option	(6,400,000)	0
Proceeds from disposition of real estate properties	27,723,000	9,593,000
Purchases of marketable securities	0	(2,495,000)
Proceeds from sales of marketable securities	56,449,000	3,750,000
Net cash used in investing activities	(300,166,000)	(158,746,000)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	94,600,000	(157,000,000)
Proceeds from issuance of secured debt	0	78,084,000
Borrowings on term loan	75,000,000	225,000,000
Payments on term loans	(573,000)	(554,000)
Debt issuance costs	(114,000)	(2,362,000)
Equity offerring costs	0	(275,000)
Value of shares withheld from options exercised for employee tax withholding	(1,135,000)	0
Proceeds from stock issuance	104,190,000	1,000
Distributions to noncontrolling interest	(1,305,000)	(1,308,000)
Distribution to acquire non-controlling interest	(6,462,000)	0
Dividends paid to stockholders	(102,440,000)	(92,726,000)
Net cash provided by (used in) financing activities	161,761,000	48,860,000
(Decrease) increase in cash and cash equivalents	(9,089,000)	10,910,000
Cash and cash equivalents, beginning of year	13,286,000	3,287,000
Cash and cash equivalents, end of year	4,197,000
Supplemental disclosure of cash flow information:
Interest Paid	27,395,000	21,029,000
Supplemental schedule of non-cash investing and financing activities:
Change in accounts payable related to acquisition of non-controlling interest	10,546,000	0
Long-term escrow deposit	4,500,000	0
Contingent consideration in asset acquisition	0	750,000
Accounts payable related to investments in real estate	980,000	686,000
Reclass of note balance into real estate investment	9,753,000	255,000
Transfer of lease escrow deposit to marketable securities	$ 0	$ 21,277,000