Investment Securities, Available-for-sale Securities, Gross Unrealized Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	$ 0	$ 242,473
12 months or more - Fair Value	30,579	264,996
Total - Fair Value	30,579	507,468
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	0	2,501
12 months or more - Gross Unrealized Loss	86	5,452
Total - Gross Unrealized Loss	86	7,953
U. S. Government Sponsored Enterprises [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value		41,786
12 months or more - Fair Value		9,932
Total - Fair Value		51,718
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss		113
12 months or more - Gross Unrealized Loss		68
Total - Gross Unrealized Loss		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	0	187,605
12 months or more - Fair Value	15,203	167,549
Total - Fair Value	15,203	355,153
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	0	2,147
12 months or more - Gross Unrealized Loss	14	3,179
Total - Gross Unrealized Loss	14	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	0	7,529
12 months or more - Fair Value	15,376	82,888
Total - Fair Value	15,376	90,417
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	0	111
12 months or more - Gross Unrealized Loss	72	2,093
Total - Gross Unrealized Loss	$ 72	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		5,553
12 months or more - Fair Value		4,627
Total - Fair Value		10,180
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss		130
12 months or more - Gross Unrealized Loss		112
Total - Gross Unrealized Loss		$ 242