CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:
Net earnings	$ 12,447	$ 12,456	$ 51,700
Adjustments to reconcile net earnings to net cash flow provided by operating activities:
Depreciation and amortization expense	13,700	10,336	9,738
Impairment charges	13,942	20,226
Gains on dispositions of real estate	(6,866)	(968)	(1,705)
Deferred rent receivable, net of allowance	(4,368)	(453)	96
Allowance for deferred rent and accounts receivable	15,903	28,879	229
Amortization of above-market and below-market leases	(285)	(685)	(1,260)
Amortization of credit agreement origination costs	3,396	207	304
Accretion expense	3,174	899	775
Stock-based employee compensation expense	757	643	480
Changes in assets and liabilities:
Accounts receivable, net	(15,848)	(14,890)	(189)
Prepaid expenses and other assets	(8,004)	151	(379)
Environmental remediation obligations	(9,009)	(1,981)	(2,512)
Accounts payable and accrued liabilities	(3,054)	5,935	(213)
Net cash flow provided by operating activities	15,885	60,755	57,064
CASH FLOWS FROM INVESTING ACTIVITIES:
Property acquisitions and capital expenditures	(4,148)	(167,495)	(4,725)
Proceeds from dispositions of real estate	9,855	2,317	2,858
(Increase) decrease in cash held for property acquisitions	(1,615)	(750)	2,665
Amortization of (accretion in) investment in direct financing leases	728	505	(323)
Issuance of notes mortgages and other receivables	(2,972)	(30,400)
Collection of notes and mortgages receivable	1,703	2,679	158
Net cash flow provided by (used in) investing activities	3,551	(193,144)	633
CASH FLOWS FROM FINANCING ACTIVITIES:
Borrowings under credit agreement	4,000	247,253	163,500
Repayments under credit agreement	(1,410)	(140,853)	(273,400)
Repayments under term loan agreement	(780)	(780)	(780)
Payments of capital lease obligations	(152)	(59)
Payments of cash dividends	(8,404)	(63,436)	(52,332)
Payments of loan origination costs	(4,144)	(175)
Cash paid in settlement of restricted stock units	(18)
Security deposits received	650	29	182
Net proceeds from issuance of common stock		91,986	108,205
Net cash flow provided by (used in) financing activities	(10,258)	133,965	(54,625)
Net increase in cash and cash equivalents	9,178	1,576	3,072
Cash and cash equivalents at beginning of year	7,698	6,122	3,050
Cash and cash equivalents at end of year	16,876	7,698	6,122
Supplemental disclosures of cash flow information Cash paid (refunded) during the period for:
Interest paid	6,293	5,523	4,863
Income taxes, net	810	267	365
Environmental remediation obligations	4,889	3,598	4,667
Non-cash transactions
Issuance of mortgages related to property dispositions	$ 4,568	$ 1,068