Loans and Asset Quality Information (Summary of Nonperforming Assets) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014
ASSET QUALITY DATA
Nonaccrual loans	$ 56,012		$ 60,574
Foreclosed real estate - non-covered	8,978		9,771		11,740
Foreclosed real estate - covered	2,055		2,350		19,504
Total nonperforming assets	104,916		114,011		141,123
Non-covered nonperforming Assets [Member] [Member]
ASSET QUALITY DATA
Nonaccrual loans	47,416		50,066		44,129
Restructured loans - accruing	33,997		35,493		26,335
Accruing loans > 90 days past due
Total nonperforming loans	81,413		85,559		70,464
Foreclosed real estate - non-covered	8,978		9,771		11,740
Total nonperforming assets	90,391		95,330		82,204
Covered nonperforming Assets [Member]
ASSET QUALITY DATA
Nonaccrual loans	8,596	[1]	10,508	[1]	31,986	[1]
Restructured loans - accruing	3,874		5,823		7,429
Accruing loans > 90 days past due
Total nonperforming loans	12,470		16,331		39,415
Foreclosed real estate - covered	2,055		2,350		19,504
Total nonperforming assets	$ 14,525		$ 18,681		$ 58,919

[1] At March 31, 2015, December 31, 2014, and March 31, 2014, the contractual balance of the nonaccrual loans covered by FDIC loss share agreements was $14.1 million, $16.0 million, and $49.3 million, respectively.