Securities - (Details 5) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Investments in pooled trust preferred securities
Amortized Cost	$ 740,236	$ 686,405
Securities available for sale	737,006	674,248
Trust preferred securities
Investments in pooled trust preferred securities
Amortized Cost	21,793	23,749
Securities available for sale	16,992	$ 18,389
Unrealized Loss	(4,801)
XXIII
Investments in pooled trust preferred securities
Amortized Cost	8,293
Securities available for sale	5,788
Unrealized Loss	$ (2,505)
Issuers Currently in Deferral or Default (percent)	16.00%
XXIV
Investments in pooled trust preferred securities
Amortized Cost	$ 9,327
Securities available for sale	8,078
Unrealized Loss	$ (1,249)
Issuers Currently in Deferral or Default (percent)	22.00%
XXVI
Investments in pooled trust preferred securities
Amortized Cost	$ 4,173
Securities available for sale	3,126
Unrealized Loss	$ (1,047)
Issuers Currently in Deferral or Default (percent)	19.00%