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EMPLOYEE DEFINED CONTRIBUTION PLANS - (Details) - USD ($)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Retirement Benefits [Abstract]
Maximum amount of employer match per employee		$ 2,000
Meximum semi-annual amount of employer match per employee		1,000
Employer matching percent of employees' contribution	50.00%
Employer matching contribution percentage of employees' gross pay	4.00%
Maximum employer match percentage per employee	2.00%
Defined contribution expense		$ 3,200,000	$ 1,400,000	$ 600,000

X

- Definition

Defined Contribution Plan, Employer Discretionary Contribution Amount, Semi-Annual

+ References

No definition available.

+ Details

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- References

No definition available.

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X

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

+ Details

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- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

No definition available.

+ Details

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X

- Definition

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

+ References

No definition available.

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X

- Definition

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

+ References

No definition available.

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