Segment Reporting (Narrative) (Details) ft² in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 ft² loan property security segment state	Dec. 31, 2014 security
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Loans held for investment | loan	12
Real Estate Investment Segment [Member]
Segment Reporting Information [Line Items]
Loans held for investment | loan	12
Real Estate Investment Segment [Member] | Commercial Mortgage Backed Securities [Member]
Segment Reporting Information [Line Items]
Number of securities acquired | security	10	10
Real Estate Investment Segment [Member] | Consolidated Properties [Member]
Segment Reporting Information [Line Items]
Number of owned properties	4,645
Square feet of property | ft²	101.8
Number of states in which entity operates | state	49
Percentage of rentable space leased	98.40%
Real estate property, weighted average remaining lease term	11 years 6 months
Real Estate Investment Segment [Member] | Unconsolidated Properties [Member]
Segment Reporting Information [Line Items]
Number of owned properties	6