Investment Securities, Available-for-sale Securities, Gross Unrealized Loss Position (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	$ 72,793	$ 778,568
12 months or more - Fair Value	521,466	54,835
Total - Fair Value	594,259	833,403
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	266	28,184
12 months or more - Gross Unrealized Loss	12,962	2,350
Total - Gross Unrealized Loss	13,228	30,534
U. S. government sponsored enterprises [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	22,503	198,023
12 months or more - Fair Value	54,995	0
Total - Fair Value	77,498	198,023
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	17	1,724
12 months or more - Gross Unrealized Loss	504	0
Total - Gross Unrealized Loss	521	1,724
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	49,195	466,056
12 months or more - Fair Value	353,561	54,835
Total - Fair Value	402,756	520,891
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	242	17,698
12 months or more - Gross Unrealized Loss	6,995	2,350
Total - Gross Unrealized Loss	7,237	20,048
Corporate bonds [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	501	902
12 months or more - Fair Value	0	0
Total - Fair Value	501	902
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	1	1
12 months or more - Gross Unrealized Loss	0	0
Total - Gross Unrealized Loss	1	1
Small Business Administration-guaranteed participation securities [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	0	103,029
12 months or more - Fair Value	102,367	0
Total - Fair Value	102,367	103,029
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	0	8,354
12 months or more - Gross Unrealized Loss	5,175	0
Total - Gross Unrealized Loss	5,175	8,354
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	0	10,558
12 months or more - Fair Value	10,543	0
Total - Fair Value	10,543	10,558
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	0	407
12 months or more - Gross Unrealized Loss	288	0
Total - Gross Unrealized Loss	288	407
Other [Member]
Available for sale securities unrealized loss position - Fair Value [Abstract]
Less than 12 months - Fair Value	594
12 months or more - Fair Value	0
Total - Fair Value	594
Available for sale securities unrealized loss position - Gross Unrealized Loss [Abstract]
Less than 12 months - Gross Unrealized Loss	6
12 months or more - Gross Unrealized Loss	0
Total - Gross Unrealized Loss	$ 6