Fair Value Measurements (Carrying Amounts and Estimated Fair Values of Financial Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities	$ 0	$ 10,415
Loans, net of allowance of loan losses	3,710,825	3,653,288
Federal Home Loan Bank advances	1,056,129	950,722
Junior subordinated debentures	22,681	22,681
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities		10,415
Loans, net of allowance of loan losses	3,710,825	3,653,288
Time deposits	1,276,464	1,255,108
Federal Home Loan Bank advances	1,056,129	950,722
Junior subordinated debentures	22,681	22,681
Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities		10,316
Loans, net of allowance of loan losses	3,664,361	3,598,025
Time deposits	1,292,947	1,269,433
Federal Home Loan Bank advances	1,058,936	950,691
Junior subordinated debentures	19,363	19,226
Fair Value Measurement [Member] \| Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities		0
Loans, net of allowance of loan losses	0	0
Time deposits	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	0	0
Fair Value Measurement [Member] \| Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities		10,316
Loans, net of allowance of loan losses	0	0
Time deposits	1,292,947	1,269,433
Federal Home Loan Bank advances	1,058,936	950,691
Junior subordinated debentures	19,363	19,226
Fair Value Measurement [Member] \| Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Held to maturity debt securities		0
Loans, net of allowance of loan losses	3,664,361	3,598,025
Time deposits	0	0
Federal Home Loan Bank advances	0	0
Junior subordinated debentures	$ 0	$ 0

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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-SubTopic 470
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Amount of investment in debt security measured at amortized cost (held-to-maturity).

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Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

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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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Amount of time deposit liabilities, including certificates of deposit.

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