Investment Securities, Available-for-sale Securities, Gross Unrealized Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	$ 63,592	$ 242,473
12 months or more - Fair Value	223,769	264,996
Total - Fair Value	287,361	507,468
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	120	2,501
12 months or more - Gross Unrealized Loss	1,309	5,452
Total - Gross Unrealized Loss	1,429	7,953
U. S. Government Sponsored Enterprises [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	10,492	41,786
12 months or more - Fair Value	9,985	9,932
Total - Fair Value	20,477	51,718
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	8	113
12 months or more - Gross Unrealized Loss	15	68
Total - Gross Unrealized Loss	23	181
Mortgage Backed Securities and Collateralized Mortgage Obligations-Residential [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	39,789	187,605
12 months or more - Fair Value	177,396	167,549
Total - Fair Value	217,185	355,153
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	70	2,147
12 months or more - Gross Unrealized Loss	885	3,179
Total - Gross Unrealized Loss	955	5,326
Small Business Administration-Guaranteed Participation Securities [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	7,688	7,529
12 months or more - Fair Value	31,703	82,888
Total - Fair Value	39,391	90,417
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	19	111
12 months or more - Gross Unrealized Loss	386	2,093
Total - Gross Unrealized Loss	405	2,204
Mortgage Backed Securities and Collateralized Mortgage Obligations-Commercial [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	5,623	5,553
12 months or more - Fair Value	4,685	4,627
Total - Fair Value	10,308	10,180
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	23	130
12 months or more - Gross Unrealized Loss	23	112
Total - Gross Unrealized Loss	$ 46	$ 242