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Fair Value Measurements and Fair Value of Financial Instruments, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Interest Rate Swaps [Abstract] |  |  |  |  |
Reclassification of net unrealized gains (losses) on cash flow hedges from AOCI to interest expense | $ 405 | $ 14 | $ 674 | $ (36) |
Financial assets [Abstract] |  |  |  |  |
HTM securities | 532,979 |  | 532,979 |  | $ 481,871
Financial liabilities [Abstract] |  |  |  |  |
Time deposits | 864,052 |  | 864,052 |  | 806,766
Long-term debt | 73,778 |  | 73,778 |  | 88,869
Junior subordinated debt | 101,196 |  | 101,196 |  | 101,196
Carrying Amount [Member] | Level 2 [Member] |  |  |  |  |
Financial assets [Abstract] |  |  |  |  |
HTM securities | 544,163 |  | 544,163 |  | 484,073
Financial liabilities [Abstract] |  |  |  |  |
Time deposits | 864,052 |  | 864,052 |  | 806,766
Long-term debt | 73,778 |  | 73,778 |  | 88,869
Junior subordinated debt | 101,196 |  | 101,196 |  | 101,196
Carrying Amount [Member] | Level 3 [Member] |  |  |  |  |
Financial assets [Abstract] |  |  |  |  |
Net loans | 6,786,613 |  | 6,786,613 |  | 6,515,273
Estimated Fair Value [Member] | Level 2 [Member] |  |  |  |  |
Financial assets [Abstract] |  |  |  |  |
HTM securities | 532,979 |  | 532,979 |  | 481,871
Financial liabilities [Abstract] |  |  |  |  |
Time deposits | 856,646 |  | 856,646 |  | 801,294
Long-term debt | 72,379 |  | 72,379 |  | 88,346
Junior subordinated debt | 101,248 |  | 101,248 |  | 104,593
Estimated Fair Value [Member] | Level 3 [Member] |  |  |  |  |
Financial assets [Abstract] |  |  |  |  |
Net loans | 6,811,553 |  | 6,811,553 |  | 6,651,931
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Other Assets [Member] |  |  |  |  |
Interest Rate Swaps [Abstract] |  |  |  |  |
Derivative asset, notional amount | 625,700 |  | 625,700 |  | 481,200
Fair value of derivative asset | 18,500 |  | 18,500 |  | 200
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member] |  |  |  |  |
Interest Rate Swaps [Abstract] |  |  |  |  |
Derivative liability, notional amount | 625,700 |  | 625,700 |  | 481,200
Fair value of derivative liability | 18,500 |  | 18,500 |  | 200
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] |  |  |  |  |
Interest Rate Swaps [Abstract] |  |  |  |  |
Notional amount | 225,000 |  | 225,000 |  | 250,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] | Interest Expense [Member] |  |  |  |  |
Interest Rate Swaps [Abstract] |  |  |  |  |
Reclassification of net unrealized gains (losses) on cash flow hedges from AOCI to interest expense | 500 | $ 100 | 900 | $ (100) |
Amount expected to be reclassified as a reduction to interest expense for CF hedges | 3,000 |  | 3,000 |  |
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] | Other Assets [Member] |  |  |  |  |
Interest Rate Swaps [Abstract] |  |  |  |  |
Fair value of derivative asset | $ 4,100 |  | $ 4,100 |  | $ 3,500

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- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Amount after tax of estimated reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) expected to be realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss) within next 12 months. + References No definition available. + Details
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- Definition 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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