Allocated share based compensation expense net of tax amount per basic and diluted share.

No definition available.

Name:	mrtn_AllocatedShareBasedCompensationExpenseNetOfTaxAmountPerBasicAndDilutedShare
Namespace Prefix:	mrtn_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award annual percentage of award which vests.

+ References

No definition available.

+ Details

Name:	mrtn_ShareBasedCompensationArrangementByShareBasedPaymentAwardAnnualPercentageOfAwardWhichVests
Namespace Prefix:	mrtn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award fair value assumptions expected forfeiture rate of unvested outstanding awards.

+ References

No definition available.

+ Details

Name:	mrtn_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedForfeitureRateOfUnvestedOutstandingAwards
Namespace Prefix:	mrtn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Share based compensation arrangement by share based payment award number of shares reserved for issuance under awards outstanding.

+ References

No definition available.

+ Details

Name:	mrtn_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesReservedForIssuanceUnderAwardsOutstanding
Namespace Prefix:	mrtn_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of annual service vesting of share-based compensation awards.

+ References

No definition available.

+ Details

Name:	mrtn_ShareBasedCompensationArrangementByShareBasedPaymentAwardsAnnualServiceVestingPercentage
Namespace Prefix:	mrtn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The percent dividend settlement amount for holders of common stock in a stock split.

+ References

No definition available.

+ Details

Name:	mrtn_StockholdersEquityNoteStockSplitDividendSettlementPercent
Namespace Prefix:	mrtn_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.F)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(1)(i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after tax, of expense for award under share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_AllocatedShareBasedCompensationExpenseNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-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

Name:	us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
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

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

+ 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)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash inflow from exercise of option under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=SL79508275-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 14
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3255-108585

+ Details

Name:	us-gaap_ProceedsFromStockOptionsExercised
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ 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 (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- 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

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 (d)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Net number of non-option equity instruments granted to participants.

+ 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 (c)(1)(iv)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ 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 (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

+ 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 (d)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of options outstanding, including both vested and non-vested options.

+ 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
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- 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.

+ 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 (a)(2)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average remaining contractual term for option awards outstanding, 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 (e)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

+ 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 (c)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedInPeriodFairValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Value, before forfeiture, of shares granted under share-based payment arrangement. Excludes employee stock ownership plan (ESOP).

+ References

No definition available.

+ Details

Name:	us-gaap_StockGrantedDuringPeriodValueSharebasedCompensationGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187143-122770

+ Details

Name:	us-gaap_StockholdersEquityNoteStockSplitConversionRatio1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mrtn_RetirementSavingsPlanParticipantsLessThan50YearsOldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RetirementPlanTypeAxis=mrtn_RetirementSavingsPlanParticipantsOver50YearsOldMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_NonmonetaryTransactionTypeAxis=mrtn_StockSplitToMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_NonmonetaryTransactionTypeAxis=mrtn_StockSplitFromMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=mrtn_AwardsPaidToEmployeesUponVestingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VestingAxis=mrtn_OneHalfOfAwardsPaidImmediatelyUponVestingAndOneHalfCreditedToEmployeesAccountsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=mrtn_UnvestedServiceBasedOptionAwardsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=mrtn_UnvestedPerformanceUnitAwardsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=mrtn_ServiceBasedOptionsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mrtn_The2015EquityIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=mrtn_FullValueAwardsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PlanNameAxis=mrtn_The2005StockIncentivePlanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Note 13 - Employee Benefits (Details Textual)					1 Months Ended											5 Months Ended	12 Months Ended
Note 13 - Employee Benefits (Details Textual)	Aug. 13, 2020 $ / shares shares	May 07, 2019 shares	Jul. 07, 2017	May 01, 2014 shares	May 31, 2020 shares	May 31, 2019 shares	Dec. 31, 2018 shares	Aug. 31, 2018 shares	May 31, 2018 $ / shares shares	Aug. 31, 2017 shares	May 31, 2017 shares	Aug. 31, 2016 shares	May 31, 2016 shares	May 31, 2015 shares	May 31, 2014 shares	May 31, 2015 shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted (in shares) \| shares																	1,815,956
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares									$ 0.01								$ 0.01	$ 0.01
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate Of Unvested Outstanding Awards																	1.25%
Share-based Payment Arrangement, Expense																	$ 1,851,000	$ 1,817,000	$ 3,323,000
Share-based Payment Arrangement, Expense, after Tax																	$ 1,400,000	$ 1,400,000	$ 2,600,000
Allocated Share Based Compensation Expense Net Of Tax Amount Per Basic And Diluted Share (in dollars per share) \| $ / shares																	$ 0.02	$ 0.02	$ 0.03
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number, Ending Balance (in shares) \| shares																	711,780	1,263,513
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term (Year)																	3 years 9 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value																	$ 3,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number (in shares) \| shares																	379,218
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term (Year)																	2 years 10 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value																	$ 2,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value																	4,100,000	$ 1,400,000	$ 1,500,000
Proceeds from Stock Options Exercised																	4,800,000	1,600,000	938,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value																	$ 539,000	569,000	547,000
Defined Contribution Plan, Employer Matching Contribution, Percent of Match																	35.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay																	6.00%
Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage																	20.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount																	$ 0	0	0
Defined Contribution Plan, Cost																	3,000,000.0	2,700,000	2,300,000
Retirement Savings Plan, Participants Less Than 50 Years Old [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount																	19,500
Retirement Savings Plan, Participants Over50 Years Old [Member]
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Amount																	$ 26,000
Stock Split To [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	3		5
Common Stock, Par or Stated Value Per Share (in dollars per share) \| $ / shares	$ 0.01
Stockholders' Equity Note, Stock Split, Dividend Settlement, Percent	50.00%
Stock Split from [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio	2		3
Share-based Payment Arrangement, Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding (in shares) \| shares																	107,048
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period (Year)				5 years													5 years
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding (in shares) \| shares																	604,732
Share-based Compensation Arrangement By Share-based Payment Awards, Annual Service Vesting Percentage				5.00%
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value																	$ 1,300,000
Performance Shares [Member] \| Awards Paid to Employees Upon Vesting [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted (in shares) \| shares				27,511	73,205	45,000	3,000	3,000	42,000	3,000	65,013	2,501	32,513			48,750
Performance Shares [Member] \| One Half of Awards Paid Immediately Upon Vesting and One Half Credited to Employees' Accounts [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted (in shares) \| shares						60,000			68,550		163,754		86,505	87,503
Share-based Compensation Arrangement By Share-based Payment Awards, Annual Service Vesting Percentage											10.00%
Unvested Service Based Option Awards [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total																	$ 1,100,000
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)																	2 years 9 months 18 days
Unvested Performance Unit Awards [Member]
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount, Total																	$ 2,200,000
Service Based Options [Member]
Shares Granted, Value, Share-based Payment Arrangement, before Forfeiture																	$ 160,000	$ 401,000	$ 957,000
2015 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares) \| shares		1,300,000
2015 Equity Incentive Plan [Member] \| Stock Split To [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares) \| shares	3,950,000
2015 Equity Incentive Plan [Member] \| Share-based Payment Arrangement, Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award Annual Percentage Of Award Which Vests																	20.00%
2015 Equity Incentive Plan [Member] \| Performance Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding (in shares) \| shares																	318,711
2015 Equity Incentive Plan [Member] \| Full Value Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized (in shares) \| shares		558,334
The 2005 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Granted (in shares) \| shares															91,002
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant (in shares) \| shares																	0
The 2005 Stock Incentive Plan [Member] \| Share-based Payment Arrangement, Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award Number Of Shares Reserved For Issuance Under Awards Outstanding (in shares) \| shares																	0
Minimum [Member] \| 2015 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																	7 years
Maximum [Member] \| 2015 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period (Year)																	10 years