Loans and Allowance for Loan Losses (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Changes in allowance for loan losses
Balance at beginning of period	$ 61,596	$ 72,974
Loans charged-off	(15,289)	(21,930)
Recoveries of loans previously charged off	4,224	3,756
Net charge-offs	(11,065)	(18,174)
Provision for loan losses	100	13,697
Benefit attributable to FDIC loss share agreements	1,786	(78)
Total provision for loan losses charged to operations	1,886	13,619
Provision for loan losses recorded through the FDIC loss share receivable	(1,786)	78
Reduction due to loan removals	(4,682)	(6,901)
Balance at end of period	45,949	61,596
Non-acquired loans
Changes in allowance for loan losses
Balance at beginning of period	44,378	49,367
Loans charged-off	(15,289)	(21,930)
Recoveries of loans previously charged off	4,224	3,756
Net charge-offs	(11,065)	(18,174)
Provision for loan losses	1,018	13,185
Total provision for loan losses charged to operations	1,018	13,185
Balance at end of period	34,331	44,378
Acquired loans | Credit impaired
Changes in allowance for loan losses
Balance at beginning of period	17,218	23,607
Provision for loan losses	(918)	512
Benefit attributable to FDIC loss share agreements	1,786	(78)
Total provision for loan losses charged to operations	868	434
Provision for loan losses recorded through the FDIC loss share receivable	(1,786)	78
Reduction due to loan removals	(4,682)	(6,901)
Balance at end of period	$ 11,618	$ 17,218