| **Income Tax (Tables)**                                                                          | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|--------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
||
| **Income Tax Disclosure [Abstract]**                                                             |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| Summary of differences between income taxes at federal statutory tax rate and effective tax rate | The following table summarizes the major components creating differences between income taxes at the federal statutory and the effective tax rate recorded in the consolidated statements of income for the three months ended March 31, 2016 and 2015:Three Months EndedMarch 31, 20162015Reconciliation of Federal Statutory to Actual Tax Expense:  Federal statutory income tax at 35%$8,143$7,702Tax-exempt interest income(2,026)(1,429)Stock compensation58Earnings on life insurance(517)(262)Tax credits(129)(144)Other98(41)Actual Tax Expense$5,574$5,834Effective Tax Rate24.0%26.5% |

| X                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**us-gaap_IncomeTaxDisclosureAbstract**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Tabular disclosure of the reconciliation using percentage or dollar amounts of the reported amount of income tax expense attributable to continuing operations for the year to the amount of income tax expense that would result from applying domestic federal statutory tax rates to pretax income from continuing operations.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32687-109319
+ Details**Name:**us-gaap_ScheduleOfEffectiveIncomeTaxRateReconciliationTableTextBlock**Namespace Prefix:**us-gaap_**Data Type:**nonnum:textBlockItemType**Balance Type:**na**Period Type:**duration |