Loans Held for Investment Components of Impaired Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Receivables [Abstract]
Nonaccruing loans	$ 2,471	$ 1,290	$ 1,345
Accruing loans	255	182	185
Total impaired loans	$ 2,726	$ 1,472	$ 1,530