Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Interest income:
Interest and fees on loans	$ 121,395	$ 143,181	$ 154,006
Interest on debt securities:
Taxable	8,711	8,325	9,877
Nontaxable	1,188	1,209	1,009
Interest on interest-bearing deposits	187	210	257
Dividends on equity securities	273	364	315
Total interest income	131,754	153,289	165,464
Interest expense:
Interest-bearing transaction accounts	653	461	721
Money market accounts	2,716	3,080	4,679
Savings accounts	201	225	275
Certificates of deposit:
$100 and over	5,281	5,554	7,077
Other	1,636	1,822	2,654
Subordinated debentures	1,322	3,019	4,082
Federal Home Loan Bank advances	1,799	2,938	3,054
Notes payable and other borrowings	778	1,038	625
Total interest expense	14,386	18,137	23,167
Net interest income	117,368	135,152	142,297
Provision for portfolio loan losses	4,409	(642)	8,757
Provision for purchase credit impaired loan losses	1,083	4,974	14,033
Net interest income after provision for loan losses	111,876	130,820	119,507
Noninterest income:
Wealth management revenue	6,942	7,118	7,300
Service charges on deposit accounts	7,181	6,825	5,664
Other service charges and fee income	2,953	2,717	2,504
Gain on sale of branches	0	1,044	0
Gain on sale of other real estate	1,531	3,363	2,225
Gain on state tax credits, net	2,252	2,503	2,207
Gain on sale of investment securities	0	1,295	1,156
Change in FDIC loss share receivable	(9,307)	(18,173)	(14,869)
Miscellaneous income	5,079	3,207	2,897
Total noninterest income	16,631	9,899	9,084
Noninterest expense:
Employee compensation and benefits	47,232	47,278	43,497
Occupancy	5,057	5,661	5,393
Furniture and equipment	1,470	1,616	1,636
Data processing	4,481	4,137	3,454
FDIC and other insurance	2,884	3,244	3,491
Loan legal and other real estate expense	3,936	4,496	6,732
Professional fees	3,825	4,876	5,120
FHLB prepayment penalty	2,936	2,590	0
Other	15,642	16,741	16,438
Total noninterest expense	87,463	90,639	85,761
Income before income tax expense	41,044	50,080	42,830
Income tax expense	13,871	16,976	14,534
Net income	27,173	33,104	28,296
Net income available to common shareholders	$ 27,173	$ 33,104	$ 25,101
Earnings per common share
Basic (usd per share)	$ 1.38	$ 1.78	$ 1.41
Diluted (usd per share)	$ 1.35	$ 1.73	$ 1.37