Mortgage Securities - VIE's and CDO's (Details) - Variable Interest Entity, Primary Beneficiary [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
Variable Interest Entity [Line Items]
Size/Principal outstanding	[1]	$ 3,601,468	$ 4,062,068
Assets on balance sheet	[2]	2,011	3,381
Liabilities on balance sheet		0	0
Maximum exposure to loss	[3]	2,011	3,381
Year to date loss on sale		0	0
Year to date cash flows		$ 6,287	$ 7,136

[1] Size/Principal Outstanding reflects the estimated principal of the underlying assets held by the securitization trust.

[2] Assets on balance sheet are securities issued by the entity and are recorded in the current marketable securities line item of the consolidated balance sheets.

[3] The maximum exposure to loss includes the assets held by the Company. The maximum exposure to loss assumes a total loss on the referenced assets held by the securitization trust.