CONSOLIDATED STATEMENTS OF INCOME (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 $ 92,395 $ 92,233 $ 98,614
Interest and dividends on investment securities:      
Taxable interest income 12,427 12,570 14,626
Non-taxable interest income 3,253 3,893 3,676
Total interest income 108,075 108,696 116,916
Interest expense:      
Deposits 5,123 7,099 12,496
Federal funds purchased and securities sold under agreements to repurchase 186 186 279
Short-term borrowings   15 35
Long-term debt 7 125 648
Junior subordinated debt owed to unconsolidated trusts 1,183 1,206 1,312
Total interest expense 6,499 8,631 14,770
Net interest income 101,576 100,065 102,146
Provision for loan losses 2,000 7,500 16,500
Net interest income after provision for loan losses 99,576 92,565 85,646
Other income:      
Trust fees 19,559 18,521 17,592
Commissions and brokers' fees, net 2,716 2,416 2,102
Remittance processing 9,421 8,354 8,426
Service charges on deposit accounts 12,038 11,947 11,646
Other service charges and fees 6,238 5,961 5,717
Gain on sales of loans 4,723 10,227 12,535
Security gains, net 776 553 1,597
Other 3,470 4,604 7,237
Total other income 58,941 62,583 66,852
Other expense:      
Salaries and wages 51,734 52,891 53,668
Employee benefits 9,607 10,922 11,124
Net occupancy expense of premises 8,462 8,489 8,899
Furniture and equipment expenses 4,725 4,848 5,146
Data processing 10,879 10,465 11,061
Amortization of intangible assets 2,884 3,132 3,315
Regulatory expense 2,079 2,290 2,543
OREO expense 93 503 1,303
Other 17,746 18,771 22,585
Total other expense 108,209 112,311 119,644
Income before income taxes 50,308 42,837 32,854
Income taxes 17,534 14,111 10,497
Net income 32,774 28,726 22,357
Preferred stock dividends 727 3,633 3,633
Net income available for common stockholders $ 32,047 $ 25,093 $ 18,724
Basic earnings per common share (in dollars per share) $ 0.37 $ 0.29 $ 0.22
Diluted earnings per common share (in dollars per share) $ 0.37 $ 0.29 $ 0.22