Securities (Securities Available for Sale) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 1,680,491	$ 969,359
Gross Unrealized Gains	22,551	38,606
Gross Unrealized Losses	38,931	6,300
Fair Value	1,664,111	1,001,665
Available-for-sale Securities, Gross Realized Gain (Loss) [Abstract]
Gross realized losses	170	714	250
Gross realized gains	632	4,400	384
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	961,442	561,076
Gross Unrealized Gains	10,640	16,719
Gross Unrealized Losses	23,674	5,426
Fair Value	948,408	572,369
State and Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	357,013	265,070
Gross Unrealized Gains	11,450	20,893
Gross Unrealized Losses	3,993	388
Fair Value	364,470	285,575
U.S. Government Agency and Government-Sponsored Enterprise Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	335,671	120,085
Gross Unrealized Gains	434	851
Gross Unrealized Losses	10,066	435
Fair Value	326,039	120,501
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,081	19,804
Gross Unrealized Gains	0	39
Gross Unrealized Losses	967	15
Fair Value	20,114	19,828
Other Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,284	3,324
Gross Unrealized Gains	27	104
Gross Unrealized Losses	231	36
Fair Value	$ 5,080	$ 3,392