Equity Investments in Real Estate (Details 1) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Ownership interest in equity investments:
Equity investments in real estate	$ 279,289	$ 275,133
C 1000 BV [Member]
Ownership interest in equity investments:
Ownership interest, percentage	85.00%
Equity investments in real estate	80,013	81,516
Uhaul Moving Partners Inc And Mercury Partners Lp [Member]
Ownership interest in equity investments:
Ownership interest, percentage	12.00%
Equity investments in real estate	27,805	28,019
Berry Plastics Corporation [Member]
Ownership interest in equity investments:
Ownership interest, percentage	50.00%
Equity investments in real estate	18,294	18,529
Tesco Plc [Member]
Ownership interest in equity investments:
Ownership interest, percentage	49.00%
Equity investments in real estate	16,760	17,487
Hellweg Die Profi Baumarkt Gmbh And Co KG [Member]
Ownership interest in equity investments:
Ownership interest, percentage	33.00%
Equity investments in real estate	21,254	22,827
Eroski Sociedad Cooperativa Mallorca [Member]
Ownership interest in equity investments:
Ownership interest, percentage	30.00%
Equity investments in real estate	9,133	9,336
Dicks Sporting Goods Inc [Member]
Ownership interest in equity investments:
Ownership interest, percentage	45.00%
Equity investments in real estate	4,971	5,010
BPS Partners, LLC
Ownership interest in equity investments:
Ownership interest, percentage	15.00%
Equity investments in real estate	26,402	26,253
Shelborne
Ownership interest in equity investments:
Equity investments in real estate	72,361	63,896
I-Drive Live
Ownership interest in equity investments:
Equity investments in real estate	$ 2,296	$ 2,260