Consolidated Statements Of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net income	$ 103,052,000	$ 107,182,000	$ 90,898,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	38,078,000	20,658,000	16,981,000
Amortization	2,611,000	247,000	320,000
Amortization	2,580,000	247,000	320,000
Straight-line rental income	(16,463,000)	(6,560,000)	(3,664,000)
Unamortized debt premium written off	(1,655,000)	0	0
Write-off of debt issuance costs	2,145,000	416,000	0
Loan and realty losses (recoveries), net	0	1,976,000	(2,195,000)
Gain on sale of real estate	0	(22,258,000)	(11,966,000)
Gain on payoff of mortgage note	0	0	(4,605,000)
Gain on purchase liability settlement	0	(3,256,000)	0
Net realized gains on sales of marketable securities	0	0	(30,000)
Share-based compensation	2,020,000	2,339,000	2,168,000
Income from equity-method investee	71,000	(324,000)	(45,000)
Change in operating assets and liabilities:
Equity-method investment and other assets	(2,334,000)	(659,000)	(745,000)
Accounts payable and accrued expenses	1,448,000	2,495,000	(512,000)
Deferred income	(2,830,000)	1,937,000	(339,000)
Net cash provided by operating activities	126,143,000	104,193,000	86,266,000
Cash flows from investing activities:
Investment in mortgage and other notes receivable	(4,447,000)	(11,082,000)	(16,241,000)
Collection of mortgage and other notes receivable	1,456,000	18,976,000	17,463,000
Investment in real estate	(520,505,000)	(635,971,000)	(110,601,000)
Investment in real estate development	(8,455,000)	(11,926,000)	0
Investment in renovations of existing real estate	(4,211,000)	(6,773,000)	0
Payments into facility repair escrows	(1,554,000)	0	0
Investment in equity-method investment	0	0	8,309,000
Payment of real estate purchase liability	(2,600,000)	0	(5,222,000)
Proceeds from disposition of real estate properties	0	20,952,000	22,975,000
Proceeds from sales of marketable securities	0	0	125,000
Net cash used in investing activities	(540,316,000)	(625,824,000)	(99,810,000)
Cash flows from financing activities:
Net change in borrowings under revolving credit facilities	207,000,000	103,000,000	(33,300,000)
Proceeds from convertible senior notes	200,000,000	0	0
Proceeds from issuance of secured debt	38,007,000	0	0
Borrowings on term loan	130,000,000	330,000,000	120,000,000
Payments of term loans	(328,515,000)	(99,655,000)	0
Debt issuance costs	(8,443,000)	(5,867,000)	(766,000)
Proceeds from equity offering, net	270,798,000	282,542,000	0
Proceeds from exercise of stock options	0	(146,000)	2,000
Distributions to noncontrolling interest	(2,049,000)	(1,250,000)	(177,000)
Dividends paid to stockholders	(100,650,000)	(85,145,000)	(78,925,000)
Net cash provided by (used in) financing activities	406,148,000	523,771,000	6,830,000
(Decrease) increase in cash and cash equivalents	(8,025,000)	2,140,000	(6,714,000)
Cash and cash equivalents, beginning of year	11,312,000	9,172,000	15,886,000
Cash and cash equivalents, end of year	3,287,000	11,312,000	9,172,000
Supplemental disclosure of cash flow information:
Interest Paid	22,172,000	7,964,000	3,240,000
Supplemental schedule of non-cash investing and financing activities:
Settlement of mortgage note by real estate acquisition	0	13,741,000	0
Lease escrow deposits	0	22,775,000	0
Escrow deposit for tax deferred exchange	0	23,813,000	0
Conditional consideration in asset acquisition	3,000,000	1,600,000	0
Accounts payable increase due to investments in real estate	2,091,000	3,086,000	0
Discount on mortgage note receivable purchased	2,062,000	0
Assumption of debt in real estate acquisition	7,858,000	80,528,000	19,250,000
Noncontrolling interest conveyed in acquisition	0	0	10,964,000
Assignment of net assets in equity-method investee	$ 0	$ 817,000	$ 0