Amount of cost for defined contribution plan.

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

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Balance Type:	debit
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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 employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Percentage of employer's matching contributions to a defined contribution plan that vests in a given year.

+ References

No definition available.

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- Definition

Maximum amount the employee may contribute to a defined contribution plan.

+ References

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
Employee Benefit Plans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Maximum annual contributions per employee (in usd)	$ 19
Employers matching contribution, annual vesting percentage	100.00%
Cost recognized	$ 7,300	$ 5,900	$ 6,300
Defined Contribution Plan, Tranche One
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	100.00%
Employer matching contribution, percent of employees' gross pay	3.00%
Defined Contribution Plan, Tranche Two
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution, percent of match	50.00%
Employer matching contribution, percent of employees' gross pay	2.00%