Fair Value of Financial Instruments (Fair Value of Assets and Liabilities, Measured on a Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets, at fair value	$ 5,522	$ 9,189
Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in real estate fund	1,891	1,484
CMBS	217,313	60,583
Derivative assets, at fair value	5,522	9,189
Total assets	224,726	71,256
Interest rate swap liabilities	(12,811)	(1,719)
Series D Preferred Stock embedded derivative	(11,520)	(16,736)
Contingent consideration arrangements	(4,818)
Total liabilities	(29,149)	(18,455)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in real estate fund	0	0
CMBS	0	0
Derivative assets, at fair value	0	0
Total assets	0	0
Interest rate swap liabilities	0	0
Series D Preferred Stock embedded derivative	0	0
Contingent consideration arrangements	0
Total liabilities	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in real estate fund	1,891	1,484
CMBS	0	0
Derivative assets, at fair value	5,522	9,189
Total assets	7,413	10,673
Interest rate swap liabilities	(12,811)	(1,719)
Series D Preferred Stock embedded derivative	0	0
Contingent consideration arrangements	0
Total liabilities	(12,811)	(1,719)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments in real estate fund	0	0
CMBS	217,313	60,583
Derivative assets, at fair value	0	0
Total assets	217,313	60,583
Interest rate swap liabilities	0	0
Series D Preferred Stock embedded derivative	(11,520)	(16,736)
Contingent consideration arrangements	(4,818)
Total liabilities	$ (16,338)	$ (16,736)