Investment Securities (Details Textuals) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Proceeds from sales of investment securities	$ 1,000,000		$ 1,065,328	$ 80,362	$ 102,011
Federal Home Loan Bank Stock	88,000		88,000		118,000
Federal Reserve Bank Stock	73,000		73,000		71,000
Investment securities gains, net	1,242	$ 34	1,242	412	$ 494
Proceeds from the sale of FHLB stock	$ 43,000		$ 42,514	$ 0