Investment Securities (Details 4) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Investments, Debt and Equity Securities [Abstract]
Taxable interest	$ 7,323	$ 7,577	$ 7,850	$ 22,373	$ 22,438
Non-taxable interest	6,058	4,808	3,343	14,760	10,004
Dividend income	574	2,185	1,138	3,587	2,698
Total interest income on investment securities	$ 13,955	$ 14,570	$ 12,331	$ 40,720	$ 35,140