Investment Securities, at Fair Value (Narrative) (Details)	9 Months Ended
	Sep. 30, 2016 USD ($) security	Dec. 31, 2015 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Investment securities, at fair value	$ 48,098,000	$ 53,304,000
CMBS [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of securities owned | security	8	10
Investment securities, at fair value	$ 48,098,000	$ 53,304,000
Number of securities paid in full prior to maturity | security	2
Carrying value of security paid in full (less than)	$ 100,000
Number of securities with fair value below amortized cost | security	6
Other-than-temporary impairment losses	$ 0
CMBS [Member] | Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Interest rate	5.88%
CMBS [Member] | Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Interest rate	8.95%