Fair Value Measurements (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
ASSETS
SECURITIES HELD TO MATURITY	$ 209,090		$ 178,318
Held to Maturity, Fair Value, Total	215,410		185,824
LOANS, NET OF ALLOWANCE FOR LOAN LOSSES	4,435,572		4,467,177
TIME CERTIFICATES OF DEPOSITS [Member]
LIABILITIES
Financial Liabilities, Book Value	768,266	[1]	753,125	[1]
Accrued Liabilities, Fair Value Disclosure	774,108	[1]	759,516	[1]
FEDERAL HOME LOAN BANK ADVANCES [Member]
LIABILITIES
Financial Liabilities, Book Value	267,091	[1]	283,569	[1]
Accrued Liabilities, Fair Value Disclosure	275,970	[1]	293,580	[1]
WHOLESALE AND CUSTOMER REPURCHASE AGREEMENTS [Member]
LIABILITIES
Financial Liabilities, Book Value	179,618	[1]	203,359	[1]
Accrued Liabilities, Fair Value Disclosure	181,752	[1]	201,189	[1]
JUNIOR SUBORDINATED DEBENTURES [Member]
LIABILITIES
Financial Liabilities, Book Value	74,073	[2]	74,127	[2]
Accrued Liabilities, Fair Value Disclosure	74,905	[2]	74,416	[2]
SUBORDINATED DEBENTURES [Member]
LIABILITIES
Financial Liabilities, Book Value	30,000	[1]	30,000	[1]
Accrued Liabilities, Fair Value Disclosure	22,084	[1]	22,762	[1]
U.S. Treasury Securities [Member]
ASSETS
SECURITIES HELD TO MATURITY	1,013	[3]	1,013	[3]
Held to Maturity, Fair Value, Total	1,126	[3]	1,134	[3]
Agency Mortgage-Backed Securities [Member]
ASSETS
SECURITIES HELD TO MATURITY	63,897	[3]	72,360	[3]
Held to Maturity, Fair Value, Total	67,595	[3]	76,593	[3]
Agency Collateralized Mortgage Obligations [Member]
ASSETS
SECURITIES HELD TO MATURITY	136,745	[3]	97,507	[3]
Held to Maturity, Fair Value, Total	138,907	[3]	100,380	[3]
State County and Municipal Securities [Member]
ASSETS
SECURITIES HELD TO MATURITY	916	[3]	915	[3]
Held to Maturity, Fair Value, Total	930	[3]	926	[3]
Single Issuer Trust Preferred Securities Issued by Banks [Member]
ASSETS
SECURITIES HELD TO MATURITY	1,513	[3]	1,516	[3]
Held to Maturity, Fair Value, Total	1,530	[3]	1,526	[3]
Corporate Debt Securities [Member]
ASSETS
SECURITIES HELD TO MATURITY	5,006	[3]	5,007	[3]
Held to Maturity, Fair Value, Total	5,322	[3]	5,265	[3]
Loans Net Of Allowance For Loan Loses [Member]
ASSETS
LOANS, NET OF ALLOWANCE FOR LOAN LOSSES	4,435,572	[4]	4,467,177	[4]
Loans Receivable, Fair Value Disclosure	4,410,461	[4]	4,462,580	[4]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | TIME CERTIFICATES OF DEPOSITS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | FEDERAL HOME LOAN BANK ADVANCES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | WHOLESALE AND CUSTOMER REPURCHASE AGREEMENTS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | JUNIOR SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[2]		[2]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | U.S. Treasury Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agency Mortgage-Backed Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Agency Collateralized Mortgage Obligations [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | State County and Municipal Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Single Issuer Trust Preferred Securities Issued by Banks [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Corporate Debt Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Loans Net Of Allowance For Loan Loses [Member]
ASSETS
Loans Receivable, Fair Value Disclosure		[4]		[4]
Significant Other Observable Inputs (Level 2) [Member] | TIME CERTIFICATES OF DEPOSITS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	774,108	[1]	759,516	[1]
Significant Other Observable Inputs (Level 2) [Member] | FEDERAL HOME LOAN BANK ADVANCES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	275,970	[1]	293,580	[1]
Significant Other Observable Inputs (Level 2) [Member] | WHOLESALE AND CUSTOMER REPURCHASE AGREEMENTS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Other Observable Inputs (Level 2) [Member] | JUNIOR SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	74,905	[2]	74,416	[2]
Significant Other Observable Inputs (Level 2) [Member] | SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Other Observable Inputs (Level 2) [Member] | U.S. Treasury Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total	1,126	[3]	1,134	[3]
Significant Other Observable Inputs (Level 2) [Member] | Agency Mortgage-Backed Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total	67,595	[3]	76,593	[3]
Significant Other Observable Inputs (Level 2) [Member] | Agency Collateralized Mortgage Obligations [Member]
ASSETS
Held to Maturity, Fair Value, Total	138,907	[3]	100,380	[3]
Significant Other Observable Inputs (Level 2) [Member] | State County and Municipal Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total	930	[3]	926	[3]
Significant Other Observable Inputs (Level 2) [Member] | Single Issuer Trust Preferred Securities Issued by Banks [Member]
ASSETS
Held to Maturity, Fair Value, Total	1,530	[3]	1,526	[3]
Significant Other Observable Inputs (Level 2) [Member] | Corporate Debt Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total	5,322	[3]	5,265	[3]
Significant Other Observable Inputs (Level 2) [Member] | Loans Net Of Allowance For Loan Loses [Member]
ASSETS
Loans Receivable, Fair Value Disclosure		[4]		[4]
Significant Unobservable Inputs (Level 3) [Member] | TIME CERTIFICATES OF DEPOSITS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Unobservable Inputs (Level 3) [Member] | FEDERAL HOME LOAN BANK ADVANCES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Unobservable Inputs (Level 3) [Member] | WHOLESALE AND CUSTOMER REPURCHASE AGREEMENTS [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	181,752	[1]	201,189	[1]
Significant Unobservable Inputs (Level 3) [Member] | JUNIOR SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[2]		[2]
Significant Unobservable Inputs (Level 3) [Member] | SUBORDINATED DEBENTURES [Member]
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	22,084	[1]	22,762	[1]
Significant Unobservable Inputs (Level 3) [Member] | U.S. Treasury Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | Agency Mortgage-Backed Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | Agency Collateralized Mortgage Obligations [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | State County and Municipal Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | Single Issuer Trust Preferred Securities Issued by Banks [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | Corporate Debt Securities [Member]
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) [Member] | Loans Net Of Allowance For Loan Loses [Member]
ASSETS
Loans Receivable, Fair Value Disclosure	$ 4,410,461	[4]	$ 4,462,580	[4]

[1] Fair value was determined by discounting anticipated future cash payments using rates currently available for instruments with similar remaining maturities.

[2] Fair value was determined based upon market prices of securities with similar terms and maturities.

[3] The fair values presented are based on quoted market prices, where available. If quoted market prices are not available, fair values are based on quoted market prices of comparable instruments and/or discounted cash flow analyses.

[4] Fair value is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities or cash flows.