Fair Value Measurements (Details 3) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Document Period End Date	Sep. 30, 2014
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	$ 372,418		$ 350,652
Held to Maturity, Fair Value, Total	373,465		346,455
LOANS, NET OF ALLOWANCE FOR LOAN LOSSES	4,892,850		4,665,068
LIABILITIES
Subordinated Debt	30,000		30,000
Junior Subordinated Debenture Owed to Unconsolidated Subsidiary Trust	73,741		73,906
Wholesale Repurchase Agreements	50,000		50,000
Customer Repurchase Agreements and other short-term borrowings	153,192		154,288
Time certificates of deposits (c)
LIABILITIES
Financial Liabilities, Book Value	672,464	[1]	743,628	[1]
Accrued Liabilities, Fair Value Disclosure	674,280	[1]	746,908	[1]
Federal Home Loan Bank borrowings (c)
LIABILITIES
Financial Liabilities, Book Value			140,294	[1]
Accrued Liabilities, Fair Value Disclosure	60,087	[1]	140,321	[1]
Customer repurchase agreements and other short-term borrowings (c)
LIABILITIES
Financial Liabilities, Book Value			154,288	[1]
Accrued Liabilities, Fair Value Disclosure	153,192	[1]	154,349	[1]
Wholesale repurchase agreements (c)
LIABILITIES
Financial Liabilities, Book Value			50,000	[1]
Accrued Liabilities, Fair Value Disclosure	50,678	[1]	51,298	[1]
Junior subordinated debentures (d)
LIABILITIES
Financial Liabilities, Book Value			73,906	[2]
Accrued Liabilities, Fair Value Disclosure	73,289	[2]	67,481	[2]
Subordinated debentures (c)
LIABILITIES
Financial Liabilities, Book Value			30,000	[1]
Accrued Liabilities, Fair Value Disclosure	28,588	[1]	28,396	[1]
U.S. Treasury securities
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	1,010	[3]	1,011	[3]
Held to Maturity, Fair Value, Total	1,060	[3]	1,042	[3]
Agency mortgage-backed securities
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	164,531	[3]	155,067	[3]
Held to Maturity, Fair Value, Total	168,000	[3]	155,951	[3]
Agency collateralized mortgage obligations
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	199,950	[3]	187,388	[3]
Held to Maturity, Fair Value, Total	197,277	[3]	182,036	[3]
State, county, and municipal securities
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	424		678
Held to Maturity, Fair Value, Total	433	[3]	685	[3]
Single issuer trust preferred securities issued by banks
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	1,500	[3]	1,503	[3]
Held to Maturity, Fair Value, Total	1,530	[3]	1,526	[3]
Corporate debt securities
ASSETS
Held to Maturity, Amortized Cost, Net debt securities	5,003	[3]	5,005	[3]
Held to Maturity, Fair Value, Total	5,165	[3]	5,215	[3]
Loans, net of allowance for loan losses (b)
ASSETS
LOANS, NET OF ALLOWANCE FOR LOAN LOSSES	4,892,850	[4]	4,665,068	[4]
Loans Receivable, Fair Value Disclosure	4,855,967	[4]	4,655,920	[4]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Time certificates of deposits (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Federal Home Loan Bank borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Customer repurchase agreements and other short-term borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Wholesale repurchase agreements (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Junior subordinated debentures (d)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[2]		[2]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Subordinated debentures (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Quoted Prices in Active Markets for Identical Assets (Level 1) | U.S. Treasury securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agency mortgage-backed securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Agency collateralized mortgage obligations
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | State, county, and municipal securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Single issuer trust preferred securities issued by banks
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Corporate debt securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Quoted Prices in Active Markets for Identical Assets (Level 1) | Loans, net of allowance for loan losses (b)
ASSETS
Loans Receivable, Fair Value Disclosure		[4]		[4]
Significant Other Observable Inputs (Level 2) | Time certificates of deposits (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	674,280	[1]	746,908	[1]
Significant Other Observable Inputs (Level 2) | Federal Home Loan Bank borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	60,087	[1]	140,321	[1]
Significant Other Observable Inputs (Level 2) | Customer repurchase agreements and other short-term borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Other Observable Inputs (Level 2) | Wholesale repurchase agreements (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Other Observable Inputs (Level 2) | Junior subordinated debentures (d)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	73,289	[2]	67,481	[2]
Significant Other Observable Inputs (Level 2) | Subordinated debentures (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Other Observable Inputs (Level 2) | U.S. Treasury securities
ASSETS
Held to Maturity, Fair Value, Total			1,042	[3]
Significant Other Observable Inputs (Level 2) | Agency mortgage-backed securities
ASSETS
Held to Maturity, Fair Value, Total			155,951	[3]
Significant Other Observable Inputs (Level 2) | Agency collateralized mortgage obligations
ASSETS
Held to Maturity, Fair Value, Total			182,036	[3]
Significant Other Observable Inputs (Level 2) | State, county, and municipal securities
ASSETS
Held to Maturity, Fair Value, Total			685
Significant Other Observable Inputs (Level 2) | Single issuer trust preferred securities issued by banks
ASSETS
Held to Maturity, Fair Value, Total			1,526	[3]
Significant Other Observable Inputs (Level 2) | Corporate debt securities
ASSETS
Held to Maturity, Fair Value, Total			5,215	[3]
Significant Other Observable Inputs (Level 2) | Loans, net of allowance for loan losses (b)
ASSETS
Loans Receivable, Fair Value Disclosure		[4]		[4]
Significant Unobservable Inputs (Level 3) | Time certificates of deposits (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Unobservable Inputs (Level 3) | Federal Home Loan Bank borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[1]		[1]
Significant Unobservable Inputs (Level 3) | Customer repurchase agreements and other short-term borrowings (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	153,192	[1]	154,349	[1]
Significant Unobservable Inputs (Level 3) | Wholesale repurchase agreements (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	50,678	[1]	51,298	[1]
Significant Unobservable Inputs (Level 3) | Junior subordinated debentures (d)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure		[2]		[2]
Significant Unobservable Inputs (Level 3) | Subordinated debentures (c)
LIABILITIES
Accrued Liabilities, Fair Value Disclosure	28,588	[1]	28,396	[1]
Significant Unobservable Inputs (Level 3) | U.S. Treasury securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | Agency mortgage-backed securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | Agency collateralized mortgage obligations
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | State, county, and municipal securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | Single issuer trust preferred securities issued by banks
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | Corporate debt securities
ASSETS
Held to Maturity, Fair Value, Total		[3]		[3]
Significant Unobservable Inputs (Level 3) | Loans, net of allowance for loan losses (b)
ASSETS
Loans Receivable, Fair Value Disclosure	4,855,967	[4]	4,655,920	[4]
Assets Held-for-sale [Member] | Fair Value, Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Mortgage Loans	12,580		8,882
Assets Held-for-sale [Member] | Fair Value, Measurements, Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Mortgage Loans
Assets Held-for-sale [Member] | Fair Value, Measurements, Recurring [Member] | Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Disposal Group, Including Discontinued Operation, Mortgage Loans

[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.