FAIR VALUE DISCLOSURES (Schedule of Items Measured on a Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	$ 1,461,552	$ 1,611,745
U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	217,193	275,899
Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,027,567	1,105,787
Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	837	856
State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	30,911	31,557
Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	183,335	196,203
Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,709	1,443
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	28,866	25,548
Servicing rights	19,106	18,854
Total assets, fair value disclosure (recurring)	1,509,752	1,656,660
Liabilities, Fair Value Disclosure [Abstract]
Nonqualified deferred compensation plan	6,575	6,641
Total liabilities, fair value disclosure (recurring)	6,575	6,641
Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	378	217
Fair Value, Measurements, Recurring [Member] | Forward commitments to sell mortgage-backed securities [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	(150)	296
Fair Value, Measurements, Recurring [Member] | U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	217,193	275,899
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,027,567	1,105,787
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	837	856
Fair Value, Measurements, Recurring [Member] | State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	30,911	31,557
Fair Value, Measurements, Recurring [Member] | Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	183,335	196,203
Fair Value, Measurements, Recurring [Member] | Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,709	1,443
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	0	0
Servicing rights	0	0
Total assets, fair value disclosure (recurring)	1,709	1,443
Liabilities, Fair Value Disclosure [Abstract]
Nonqualified deferred compensation plan	6,575	6,641
Total liabilities, fair value disclosure (recurring)	6,575	6,641
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Forward commitments to sell mortgage-backed securities [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,709	1,443
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	28,866	25,548
Servicing rights	0	0
Total assets, fair value disclosure (recurring)	1,488,937	1,636,363
Liabilities, Fair Value Disclosure [Abstract]
Nonqualified deferred compensation plan	0	0
Total liabilities, fair value disclosure (recurring)	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	378	217
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Forward commitments to sell mortgage-backed securities [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	(150)	296
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	217,193	275,899
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,027,567	1,105,787
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	837	856
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	30,911	31,557
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	183,335	196,203
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	0	0
Servicing rights	19,106	18,854
Total assets, fair value disclosure (recurring)	19,106	18,854
Liabilities, Fair Value Disclosure [Abstract]
Nonqualified deferred compensation plan	0	0
Total liabilities, fair value disclosure (recurring)	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Forward commitments to sell mortgage-backed securities [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	0	0
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	$ 0	$ 0