Investment Securities (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Schedule of Available-for-sale Securities [Line Items]
AFS securities pledged as collateral	$ 339,800		$ 339,800
Proceeds from sales of securities available-for-sale			185,533	$ 392,841
Gross realized gains on sale of securities	1,300	$ 1,000	3,300	10,600
Gross realized losses on sale of securities	(100)	(600)	(500)	(1,600)
Available-for-sale Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Proceeds from sales of securities available-for-sale	$ 98,300	$ 39,100	$ 182,700	$ 383,900