Condensed Consolidating Financial Information - Condensed Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	$ 1,295,229	$ 1,262,099
Real estate held for sale		16,497
Mortgage loans	368,650	368,650
Net investment in direct financing leases	391,904	314,412
Gross investment in real estate assets	2,055,783	1,961,658
Accumulated depreciation and amortization	(141,877)	(124,615)
Net investment in real estate assets	1,913,906	1,837,043
Cash and cash equivalents	26,072	37,311	127,639	102,726
Interest and rent receivable	54,231	45,289
Straight-line rent receivable	41,347	35,860
Other loans	157,251	159,243
Other assets	61,669	64,140
Total Assets	2,254,476	2,178,886
Debt, net	929,074	1,025,160
Accounts payable and accrued expenses	58,694	65,961
Deferred revenue	25,413	20,609
Lease deposits and other obligations to tenants	18,455	17,342
Total liabilities	1,031,636	1,129,072
Total equity	1,222,840	1,049,814
Total Liabilities and Capital	2,254,476	2,178,886
Parent
Condensed Financial Statements, Captions [Line Items]
Net intercompany receivable	29,654	27,393
Investment in subsidiaries	1,223,231	1,050,204
Total Assets	1,252,885	1,077,597
Accounts payable and accrued expenses	30,045	27,783
Total liabilities	30,045	27,783
Total equity	1,222,840	1,049,814
Total Liabilities and Capital	1,252,885	1,077,597
Subsidiary Issuers
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets		28
Gross investment in real estate assets		28
Net investment in real estate assets		28
Cash and cash equivalents	25,923	35,483	125,655	101,230
Interest and rent receivable	700	212
Other loans	178	177
Net intercompany receivable	1,371,376	1,373,941
Investment in subsidiaries	736,536	647,029
Other assets	29,517	31,097
Total Assets	2,164,230	2,087,967
Debt, net	915,000	1,010,962
Accounts payable and accrued expenses	26,026	26,658
Deferred revenue	(27)	143
Total liabilities	940,999	1,037,763
Total equity	1,223,231	1,050,204
Total Liabilities and Capital	2,164,230	2,087,967
Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	1,229,282	1,196,124
Mortgage loans	268,650	268,650
Net investment in direct financing leases	185,913	110,155
Gross investment in real estate assets	1,683,845	1,574,929
Accumulated depreciation and amortization	(134,575)	(118,163)
Net investment in real estate assets	1,549,270	1,456,766
Cash and cash equivalents		1,565	1,565	1,409
Interest and rent receivable	29,376	29,159
Straight-line rent receivable	33,821	29,314
Investment in subsidiaries	43,649	42,666
Other assets	2,176	1,522
Total Assets	1,658,292	1,560,992
Accounts payable and accrued expenses	1,814	10,492
Net intercompany payable	1,022,643	1,000,117
Deferred revenue	19,410	19,621
Lease deposits and other obligations to tenants	16,677	16,606
Total liabilities	1,060,544	1,046,836
Total equity	597,748	514,156
Total Liabilities and Capital	1,658,292	1,560,992
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	65,947	65,947
Real estate held for sale		16,497
Mortgage loans	100,000	100,000
Net investment in direct financing leases	205,991	204,257
Gross investment in real estate assets	371,938	386,701
Accumulated depreciation and amortization	(7,302)	(6,452)
Net investment in real estate assets	364,636	380,249
Cash and cash equivalents	149	263	419	87
Interest and rent receivable	24,155	15,918
Straight-line rent receivable	7,526	6,546
Other loans	157,073	159,066
Other assets	29,976	31,521
Total Assets	583,515	593,563
Debt, net	14,074	14,198
Accounts payable and accrued expenses	809	1,028
Net intercompany payable	378,387	401,217
Deferred revenue	6,030	845
Lease deposits and other obligations to tenants	1,778	736
Total liabilities	401,078	418,024
Total equity	182,437	175,539
Total Liabilities and Capital	583,515	593,563
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net intercompany receivable	(1,404,030)	(1,401,334)
Investment in subsidiaries	(2,003,416)	(1,739,899)
Total Assets	(3,404,446)	(3,141,233)
Net intercompany payable	(1,401,030)	(1,401,334)
Total liabilities	(1,401,030)	(1,401,334)
Total equity	(2,003,416)	(1,739,899)
Total Liabilities and Capital	$ (3,404,446)	$ (3,141,233)