Securities Fair Value Option Securities (Details) - USD ($) $ in Thousands |
Dec. 31, 2016 |
Dec. 31, 2015 |
---|---|---|
Schedule of Fair Value Option Securities [Line Items] | ||
Fair Value Option Securities, Fair Value | $ 77,046 | $ 444,217 |
U.S. government agency residential mortgage-backed securities [Member] | ||
Schedule of Fair Value Option Securities [Line Items] | ||
Fair Value Option Securities, Fair Value | 77,046 | 444,217 |
Fair Value Option Securities, Net Unrealized Gain (Loss) | $ (1,777) | $ (2,060) |