XML 43 R36.htm IDEA: XBRL DOCUMENT
v3.25.3

Leases (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2025
Leases [Abstract] |
Schedule of Components of Operating Lease Expense | The following table presents the components of operating lease expense for the three and nine months ended September 30, 2025 and 2024:
|  |  |  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
Lease cost: |  | Classification |  | 2025 |  |  | 2024 |  |  | 2025 |  |  | 2024 |
|  |  |  | (In thousands) |
Operating lease cost - office space |  | Occupancy |  | $ | 2,868 |  |  | $ | 2,774 |  |  | $ | 8,445 |  |  | $ | 8,278 |
Operating lease cost - equipment |  | Technology and communications |  |  | 97 |  |  |  | 98 |  |  |  | 293 |  |  |  | 293 |
Variable lease costs |  | Occupancy |  |  | 908 |  |  |  | 975 |  |  |  | 2,540 |  |  |  | 2,444 |
Total operating lease cost |  |  |  | $ | 3,873 |  |  | $ | 3,847 |  |  | $ | 11,278 |  |  | $ | 11,015 |
Summary of Weighted Average Remaining Lease Term and Discount Rate | The weighted average remaining lease term and weighted average discount rate are as follows:
|  | As of |
Lease Term and Discount Rate |  | September 30, 2025 |  |  | December 31, 2024 |
Weighted average remaining lease term (in years) - operating leases |  |  | 8.2 |  |  |  | 8.8 |
Weighted average discount rate - operating leases |  |  | 6.1 | % |  |  | 6.1 | %
Weighted average remaining lease term (in years) - finance leases |  |  | — |  |  |  | 0.8 |
Weighted average discount rate - finance leases |  |  | — |  |  |  | 7.2 | %
Schedule of Maturity of Lease Liabilities | The following table presents the maturity of lease liabilities as of September 30, 2025:
|  | Operating Leases |  |  |
|  | (In thousands) |  |  |
Remainder of 2025 |  | $ | 3,269 |  |  |
2026 |  |  | 12,489 |  |  |
2027 |  |  | 9,448 |  |  |
2028 |  |  | 8,731 |  |  |
2029 |  |  | 9,006 |  |  |
2030 and thereafter |  |  | 42,154 |  |  |
Total lease payments |  |  | 85,097 |  |  |
Less: imputed interest |  |  | 18,225 |  |  |
Present value of lease liabilities |  | $ | 66,872 |  |  |

X
- Definition Schedule of weighted average remaining lease term and discount rate. + References No definition available. + Details
Name: | mktx_ScheduleOfWeightedAverageRemainingLeaseTermAndDiscountRateTableTextBlock
Namespace Prefix: | mktx_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of lessee's lease cost. Includes, but is not limited to, interest expense for finance lease, amortization of right-of-use asset for finance lease, operating lease cost, short-term lease cost, variable lease cost and sublease income. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-4 + Details
Name: | us-gaap_LeaseCostTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of undiscounted cash flows of lessee's operating lease liability. Includes, but is not limited to, reconciliation of undiscounted cash flows to operating lease liability recognized in statement of financial position. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-6 + Details
Name: | us-gaap_LesseeOperatingLeaseLiabilityMaturityTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration