Secured Borrowings Secured Borrowings, Counterparty Information (Details) $ in Thousands	Mar. 31, 2016 USD ($) Agreements
Counterparty Information [Line Items]
Line of Credit Facility, Amount Outstanding	$ 272,987
Line of Credit Facility, Maximum Borrowing Capacity	$ 300,000
Line of Credit Facility, Interest Rate at Period End	1.31%
Number of Counterparties with Borrowings Outstanding | Agreements	18
Available Repurchase Agreement Counterparties | Agreements	32
Wells Fargo Bank, N. A. and affiliates [Member]
Counterparty Information [Line Items]
Repurchase Agreement Counterparty, Amount at Risk	$ 56,502
Borrowings outstanding with counterparty	$ 286,672
WAVG interest rate for amount outstanding with named counterparty	1.32%
JP Morgan Securities, LLC [Member]
Counterparty Information [Line Items]
Repurchase Agreement Counterparty, Amount at Risk	$ 49,202
Borrowings outstanding with counterparty	$ 311,455
WAVG interest rate for amount outstanding with named counterparty	1.30%