FAIR VALUE DISCLOSURES (Schedule of Items Measured on a Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	$ 1,554,442	$ 1,445,689
U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	252,552	231,731
Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,056,256	1,007,844
Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	838	837
State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	29,194	29,615
Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	213,617	173,695
Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,985	1,967
Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	43,655	31,411
Servicing rights	17,402	18,013
Total assets, fair value disclosure (recurring)	1,616,483	1,495,399
Fair Value, Measurements, Recurring [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	1,268	580
Fair Value, Measurements, Recurring [Member] | Forward commitments to sell mortgage-backed securities [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	(284)	(294)
Fair Value, Measurements, Recurring [Member] | U.S. Government sponsored agencies [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	252,552	231,731
Fair Value, Measurements, Recurring [Member] | Residential mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,056,256	1,007,844
Fair Value, Measurements, Recurring [Member] | Commercial mortgage-backed [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	838	837
Fair Value, Measurements, Recurring [Member] | State and political subdivisions [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	29,194	29,615
Fair Value, Measurements, Recurring [Member] | Corporate notes [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	213,617	173,695
Fair Value, Measurements, Recurring [Member] | Equity investments [Member]
Assets, Fair Value Disclosure [Abstract]
Available-for-sale Securities, Fair Value	1,985	1,967
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)	1,985	1,967
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	1,985	1,967
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets, Fair Value Disclosure [Abstract]
Mortgage loans held for sale	43,655	31,411
Servicing rights	0	0
Total assets, fair value disclosure (recurring)	1,597,096	1,475,419
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate lock commitments [Member]
Assets, Fair Value Disclosure [Abstract]
Derivative Assets	1,268	580
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	(284)	(294)
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	252,552	231,731
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	1,056,256	1,007,844
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	838	837
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	29,194	29,615
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	213,617	173,695
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	17,402	18,013
Total assets, fair value disclosure (recurring)	17,402	18,013
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