Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

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Loans and Allowance - Composition of Loan Portfolio by Loan Class (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Loans:
Loans	$ 3,965,532	$ 3,924,865
Allowance for loan losses	(62,801)	(63,964)	(69,583)	(67,870)
Net Loans	3,902,731	3,860,901
Commercial and industrial loans
Loans:
Loans	938,937	896,688
Agricultural production financing and other loans to farmers
Loans:
Loans	95,652	104,927
Real estate loans - Construction
Loans:
Loans	237,036	207,221
Real estate loans - Commercial and farmland
Loans:
Loans	1,646,418	1,672,661
Real estate loans - Residential
Loans:
Loans	640,451	647,315
Allowance for loan losses	(13,269)	(13,152)	(13,908)	(15,077)
Real estate loans - Home Equity
Loans:
Loans	286,914	286,529
Individuals' loans for household and other personal expenditures
Loans:
Loans	70,223	73,400
Allowance for loan losses	(3,138)	(2,658)	(2,410)	(2,515)
Lease financing receivables, net of unearned income
Loans:
Loans	853	1,106
Allowance for loan losses	(4)	(3)
Other loans
Loans:
Loans	$ 49,048	$ 35,018