Condensed Consolidating Financial Information - Condensed Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	$ 1,606,432	$ 1,262,099
Real estate held for sale		16,497
Mortgage loans	368,650	368,650
Investment in direct financing leases	403,512	314,412
Gross investment in real estate assets	2,378,594	1,961,658
Accumulated depreciation and amortization	(150,666)	(124,615)
Net investment in real estate assets	2,227,928	1,837,043
Cash and cash equivalents	12,124	37,311	36,163	102,726
Interest and rent receivable	54,505	45,289
Straight-line rent receivable	44,240	35,860
Other loans	161,245	159,243
Other assets	63,108	64,140
Total Assets	2,563,150	2,178,886
Debt, net	1,086,973	1,025,160
Accounts payable and accrued expenses	73,852	65,961
Deferred revenue	23,229	20,609
Lease deposits and other obligations to tenants	20,527	17,342
Total liabilities	1,204,581	1,129,072
Total equity	1,358,569	1,049,814
Total Liabilities and Equity	2,563,150	2,178,886
Parent
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets
Real estate held for sale
Mortgage loans
Investment in direct financing leases
Gross investment in real estate assets
Accumulated depreciation and amortization
Net investment in real estate assets
Cash and cash equivalents
Interest and rent receivable
Straight-line rent receivable
Other loans
Net intercompany receivable	32,053	27,393
Investment in subsidiaries	1,358,959	1,050,204
Total Assets	1,391,012	1,077,597
Accounts payable and accrued expenses	32,443	27,783
Net intercompany payable
Deferred revenue
Lease deposits and other obligations to tenants
Total liabilities	32,443	27,783
Total equity	1,358,569	1,049,814
Total Liabilities and Equity	1,391,012	1,077,597
Subsidiary Issuers
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets		28
Mortgage loans
Investment in direct financing leases
Gross investment in real estate assets		28
Accumulated depreciation and amortization
Net investment in real estate assets		28
Cash and cash equivalents	11,391	35,483	34,371	101,230
Interest and rent receivable	715	212
Other loans	178	177
Net intercompany receivable	1,639,081	1,373,941
Investment in subsidiaries	783,441	647,029
Other assets	32,534	31,097
Total Assets	2,467,340	2,087,967
Debt, net	1,072,960	1,010,962
Accounts payable and accrued expenses	35,705	26,658
Deferred revenue	(284)	143
Total liabilities	1,108,381	1,037,763
Total equity	1,358,959	1,050,204
Total Liabilities and Equity	2,467,340	2,087,967
Subsidiary Guarantors
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	1,259,234	1,196,124
Mortgage loans	268,650	268,650
Investment in direct financing leases	186,586	110,155
Gross investment in real estate assets	1,714,470	1,574,929
Accumulated depreciation and amortization	(142,939)	(118,163)
Net investment in real estate assets	1,571,531	1,456,766
Cash and cash equivalents		1,565	1,565	1,409
Interest and rent receivable	29,284	29,159
Straight-line rent receivable	36,051	29,314
Investment in subsidiaries	43,557	42,666
Other assets	980	1,522
Total Assets	1,681,403	1,560,992
Accounts payable and accrued expenses	4,935	10,492
Net intercompany payable	998,987	1,000,117
Deferred revenue	17,970	19,621
Lease deposits and other obligations to tenants	17,923	16,606
Total liabilities	1,039,815	1,046,836
Total equity	641,588	514,156
Total Liabilities and Equity	1,681,403	1,560,992
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets	347,198	65,947
Real estate held for sale		16,497
Mortgage loans	100,000	100,000
Investment in direct financing leases	216,926	204,257
Gross investment in real estate assets	664,124	386,701
Accumulated depreciation and amortization	(7,727)	(6,452)
Net investment in real estate assets	656,397	380,249
Cash and cash equivalents	733	263	227	87
Interest and rent receivable	24,506	15,918
Straight-line rent receivable	8,189	6,546
Other loans	161,067	159,066
Other assets	29,594	31,521
Total Assets	880,486	593,563
Debt, net	14,013	14,198
Accounts payable and accrued expenses	769	1,028
Net intercompany payable	672,147	401,217
Deferred revenue	5,543	845
Lease deposits and other obligations to tenants	2,604	736
Total liabilities	695,076	418,024
Total equity	185,410	175,539
Total Liabilities and Equity	880,486	593,563
Eliminations
Condensed Financial Statements, Captions [Line Items]
Land, buildings and improvements and intangible lease assets
Real estate held for sale
Mortgage loans
Investment in direct financing leases
Gross investment in real estate assets
Accumulated depreciation and amortization
Net investment in real estate assets
Cash and cash equivalents
Interest and rent receivable
Straight-line rent receivable
Other loans
Net intercompany receivable	(1,671,134)	(1,401,334)
Investment in subsidiaries	(2,185,957)	(1,739,899)
Total Assets	(3,857,091)	(3,141,233)
Net intercompany payable	(1,671,134)	(1,401,334)
Total liabilities	(1,671,134)	(1,401,334)
Total equity	(2,185,957)	(1,739,899)
Total Liabilities and Equity	$ (3,857,091)	$ (3,141,233)