Investments - Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Amortized cost and fair values of investment securities held-to-maturity
Amortized Cost	$ 52,969	$ 54,538
Unrealized Gain	1,336	1,600
Unrealized Loss	(382)	(267)
Securities held-to-maturity, fair value	53,923	55,871
Municipal securities
Amortized cost and fair values of investment securities held-to-maturity
Amortized Cost	52,969	54,538
Unrealized Gain	1,336	1,600
Unrealized Loss	(382)	(267)
Securities held-to-maturity, fair value	$ 53,923	$ 55,871