Securities (Unrealized Gross Losses and Estimated Fair values of Investment Securities by Length of Time that Individual Securities in Each Category in Continuous Loss Position) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	$ 386,967	$ 115,880
Unrealized Losses - Less Than 12 Months	(11,942)	(199)
Fair Value - 12 Months or More	122,236	8,174
Unrealized Losses - 12 Months or More	(7,834)	(697)
Fair Value	509,203	124,054
Unrealized Losses	(19,776)	(896)
US States and Political Subdivisions Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	2,143
Unrealized Losses - Less Than 12 Months	(11)
Fair Value - 12 Months or More	0
Unrealized Losses - 12 Months or More	0
Fair Value	2,143
Unrealized Losses	(11)
Collateralized mortgage obligations
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	239,278	73,098
Unrealized Losses - Less Than 12 Months	(7,738)	(120)
Fair Value - 12 Months or More	73,376	0
Unrealized Losses - 12 Months or More	(4,586)	0
Fair Value	312,654	73,098
Unrealized Losses	(12,324)	(120)
Private issue collateralized mortgage obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	122	0
Unrealized Losses - Less Than 12 Months	(4)	0
Fair Value - 12 Months or More	4,945	8,174
Unrealized Losses - 12 Months or More	(403)	(697)
Fair Value	5,067	8,174
Unrealized Losses	(407)	(697)
Obligations of U.S. government sponsored enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value - Less Than 12 Months	145,424	42,782
Unrealized Losses - Less Than 12 Months	(4,189)	(79)
Fair Value - 12 Months or More	43,915	0
Unrealized Losses - 12 Months or More	(2,845)	0
Fair Value	189,339	42,782
Unrealized Losses	$ (7,034)	$ (79)