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Fair Value Measurements and Fair Value of Financial Instruments, Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Dec. 31, 2018
--- | --- | ---
Financial assets [Abstract] |  |
HTM securities | $ 754,995 | $ 778,675
Carrying Amount [Member] | Level 2 [Member] |  |
Financial assets [Abstract] |  |
HTM securities | 744,601 | 783,599
Financial liabilities [Abstract] |  |
Time deposits | 976,567 | 930,678
Long-term debt | 84,267 | 73,724
Junior subordinated debt | 101,196 | 101,196
Carrying Amount [Member] | Level 3 [Member] |  |
Financial assets [Abstract] |  |
Net loans | 6,906,770 | 6,822,147
Estimated Fair Value [Member] | Level 2 [Member] |  |
Financial assets [Abstract] |  |
HTM securities | 754,995 | 778,675
Financial liabilities [Abstract] |  |
Time deposits | 973,822 | 920,534
Long-term debt | 84,878 | 73,927
Junior subordinated debt | 104,914 | 100,114
Estimated Fair Value [Member] | Level 3 [Member] |  |
Financial assets [Abstract] |  |
Net loans | $ 7,199,147 | $ 6,754,460

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- Definition Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611 + Details
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