Investment Securities (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
AFS securities pledged as collateral	$ 430,200,000		$ 430,200,000
Proceeds from sales of securities available-for-sale			86,018,000	$ 353,374,000
Gross realized gains on sale of securities	1,700,000	$ 600,000	1,900,000	9,500,000
Gross realized losses on sale of securities	(76,000)	(100,000)	(379,000)	(900,000)
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of securities available-for-sale	$ 41,400,000	$ 9,900,000	$ 84,500,000	$ 344,800,000