Loans Receivable and Other Lending Investments, net (Maturities) (Details) $ in Thousands	Mar. 31, 2018 USD ($)
Amortized Cost Basis
Within one year	$ 0
After one year through 5 years	18,878
After 5 years through 10 years	0
After 10 years	0
Amortized Cost Basis	18,878
Estimated Fair Value
Within one year	0
After one year through 5 years	19,281
After 5 years through 10 years	0
After 10 years	0
Total	19,281
Amortized Cost Basis
Within one year	0
After one year through 5 years	0
After 5 years through 10 years	0
After 10 years	21,195
Amortized Cost Basis	21,195
Estimated Fair Value
Within one year	0
After one year through 5 years	0
After 5 years through 10 years	0
After 10 years	21,835
Total	$ 21,835