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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 |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Derivatives, Fair Value [Line Items] |  |  |
Reclassification of net unrealized gain on cash flow hedges from AOCI to interest expense | $ 269 | $ (50) |
Financial assets [Abstract] |  |  |
HTM securities | 477,409 |  | $ 481,871
Financial liabilities [Abstract] |  |  |
Time deposits | 840,425 |  | 806,766
Long-term debt | 88,824 |  | 88,869
Junior subordinated debt | 101,196 |  | 101,196
Carrying Amount [Member] | Level 2 [Member] |  |  |
Financial assets [Abstract] |  |  |
HTM securities | 487,126 |  | 484,073
Financial liabilities [Abstract] |  |  |
Time deposits | 840,425 |  | 806,766
Long-term debt | 88,824 |  | 88,869
Junior subordinated debt | 101,196 |  | 101,196
Carrying Amount [Member] | Level 3 [Member] |  |  |
Financial assets [Abstract] |  |  |
Net loans | 6,576,924 |  | 6,515,273
Estimated Fair Value [Member] | Level 2 [Member] |  |  |
Financial assets [Abstract] |  |  |
HTM securities | 477,409 |  | 481,871
Financial liabilities [Abstract] |  |  |
Time deposits | 833,181 |  | 801,294
Long-term debt | 87,538 |  | 88,346
Junior subordinated debt | 101,986 |  | 104,593
Estimated Fair Value [Member] | Level 3 [Member] |  |  |
Financial assets [Abstract] |  |  |
Net loans | 6,612,392 |  | 6,651,931
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Other Assets [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative asset, notional amount | 551,800 |  | 481,200
Fair value of derivative asset | 9,200 |  | 200
Not Designated as Hedging Instrument [Member] | Interest Rate Swaps [Member] | Other Liabilities [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Derivative liability, notional amount | 551,800 |  | 481,200
Fair value of derivative liability | 9,200 |  | 200
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Notional amount | 250,000 |  | 250,000
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] | Interest Expense [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Reclassification of net unrealized gain on cash flow hedges from AOCI to interest expense | 400 | $ 100 |
Amount expected to be reclassified as a reduction to interest expense for CF hedges | 2,600 |  |
Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member] | Interest Rate Swaps [Member] | Other Assets [Member] |  |  |
Derivatives, Fair Value [Line Items] |  |  |
Fair value of derivative asset | $ 4,200 |  | $ 3,500

X
- 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 Nominal or face amount used to calculate payments on the derivative asset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959 + Details
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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=82849420&loc=SL20226000-175313 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=82924980&loc=SL51823488-111719 + Details
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- Definition Fair value of investments in debt securities classified as held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 + 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://www.xbrl.org/2003/role/presentationRef -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://www.xbrl.org/2003/role/presentationRef -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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- Definition Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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