Investment Securities, at Fair Value - Narrative (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014 security	Dec. 31, 2013 security
Investment [Line Items]
Investment securities, at fair value	$ 213,803	$ 62,067
Commercial Mortgage Backed Securities [Member]
Investment [Line Items]
Number of securities acquired		10
Investment securities, at fair value	212,155	60,583
Number of securities acquired, fair value below amortized cost	6
Commercial Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member]
Investment [Line Items]
Investment securities, at fair value	212,200	60,600
Cole Merger [Member] | Commercial Mortgage Backed Securities [Member]
Investment [Line Items]
Number of securities acquired	15
Cole Merger [Member] | Commercial Mortgage Backed Securities [Member] | Estimate of Fair Value Measurement [Member]
Investment [Line Items]
Investment securities, at fair value	$ 151,200