Securities (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Investments in pooled trust preferred securities
Amortized Cost	$ 553,770
Fair Value	553,584	501,254
Trust preferred securities
Investments in pooled trust preferred securities
Amortized Cost	26,400	27,531
Fair Value	19,756	17,671
Unrealized Gain (Loss)	(6,644)
XIII
Investments in pooled trust preferred securities
Amortized Cost	1,116
Fair Value	1,253
Unrealized Gain (Loss)	137
Issuers Currently in Deferral or Default (percent)	23.00%
XXIII
Investments in pooled trust preferred securities
Amortized Cost	8,670
Fair Value	6,156
Unrealized Gain (Loss)	(2,514)
Issuers Currently in Deferral or Default (percent)	19.00%
XXIV
Investments in pooled trust preferred securities
Amortized Cost	12,076
Fair Value	8,877
Unrealized Gain (Loss)	(3,199)
Issuers Currently in Deferral or Default (percent)	33.00%
XXVI
Investments in pooled trust preferred securities
Amortized Cost	4,538
Fair Value	3,470
Unrealized Gain (Loss)	$ (1,068)
Issuers Currently in Deferral or Default (percent)	25.00%