Employee Benefit Plans (Detail Textuals 4) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Tax benefits for compensation expense for restricted stock awards			$ 427,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum ownership considered major owner	10.00%
Percentage of fair market value of the common stock for major owners	110.00%
Vesting period	5 years
Expiration period of the stock	10 years
Expiration period of the stock of majority owners	5 years
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation award, vesting percentage	20.00%
Weighted average grant date fair value (in dollars per share)	$ 25.13	$ 21.66	$ 10.77
Total fair value of shares vested	$ 16,483,000	$ 19,480,000	$ 9,751,000
Tax benefits for compensation expense for restricted stock awards	1,899,000	$ 2,803,000	$ 427,000
Unrecognized compensation cost related to non-vested restricted shares	$ 43,498,000
Period for recognition of compensation cost related to non-vested restricted shares	3 years 2 months 12 days

This element represents the minimum threshold limit percentage of incentive stock option grants to owners.

No definition available.

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- Definition

This element represents the percentage of fair market value of the common stock.

+ References

No definition available.

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- Definition

This element represents the share based compensation arrangement by share based payment award expirations in period of majority owner.

+ References

No definition available.

+ Details

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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
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- Definition

Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation.

+ References

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Period Type:	instant

- Definition

Amount of cash inflow from realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 20
-Section 55
-Paragraph 24
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- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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-Publisher FASB
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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Percentage of vesting of share-based compensation awards.

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-Publisher FASB
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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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