Securities (Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	$ (26,156)	$ (22,551)
Less than 12 Months Fair Value	113,296	887,693
Less than 12 Months Unrealized Losses	(263)	(23,148)
12 Months or More Fair Value	629,451	166,348
12 Months or More Unrealized Losses	(17,865)	(15,783)
Total Fair Value	742,747	1,054,041
Total Unrealized Losses	(18,128)	(38,931)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	(18,128)	(38,931)
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	(11,858)	(10,640)
Less than 12 Months Fair Value	70,725	492,921
Less than 12 Months Unrealized Losses	(160)	(10,991)
12 Months or More Fair Value	296,832	121,303
12 Months or More Unrealized Losses	(11,328)	(12,684)
Total Fair Value	367,557	614,224
Total Unrealized Losses	(11,488)	(23,675)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	(11,488)	(23,674)
State and Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	(13,783)	(11,450)
Less than 12 Months Fair Value	26,340	112,400
Less than 12 Months Unrealized Losses	(101)	(3,069)
12 Months or More Fair Value	61,424	13,815
12 Months or More Unrealized Losses	(1,397)	(923)
Total Fair Value	87,764	126,215
Total Unrealized Losses	(1,498)	(3,992)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	(1,498)	(3,993)
US Government Corporations and Agencies Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	(492)	(434)
Less than 12 Months Fair Value	16,231	260,001
Less than 12 Months Unrealized Losses	(2)	(8,063)
12 Months or More Fair Value	246,776	28,447
12 Months or More Unrealized Losses	(4,442)	(2,003)
Total Fair Value	263,007	288,448
Total Unrealized Losses	(4,444)	(10,066)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	(4,444)	(10,066)
US Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	(1)	0
Less than 12 Months Fair Value	0	20,114
Less than 12 Months Unrealized Losses	0	(967)
12 Months or More Fair Value	19,288	0
12 Months or More Unrealized Losses	(559)	0
Total Fair Value	19,288	20,114
Total Unrealized Losses	(559)	(967)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	(559)	(967)
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Debt Securities Gross Unrealized Gain, instant	(22)	(27)
Less than 12 Months Fair Value	0	2,257
Less than 12 Months Unrealized Losses	0	(58)
12 Months or More Fair Value	5,131	2,783
12 Months or More Unrealized Losses	(139)	(173)
Total Fair Value	5,131	5,040
Total Unrealized Losses	(139)	(231)
Available-for-sale Debt Securities, Gross Unrealized Loss, instant	$ (139)	$ (231)