Revenue from Contracts with Customers - Schedule of Revenue, Remaining Performance Obligations (Details) $ in Thousands	Sep. 30, 2025 USD ($)
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 12,613,893
Remaining performance obligations, percent	100.00%
UNITED STATES
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 12,402,065
Remaining performance obligations, percent	98.00%
UNITED STATES \| United States Electrical Construction And Facilities Services [Member]
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 4,497,521
Remaining performance obligations, percent	35.00%
UNITED STATES \| United States Mechanical Construction And Facilities Services [Member]
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 6,421,665
Remaining performance obligations, percent	51.00%
UNITED STATES \| United States Building Services [Member]
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 1,280,681
Remaining performance obligations, percent	10.00%
UNITED STATES \| United States Industrial Services [Member]
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 202,198
Remaining performance obligations, percent	2.00%
UNITED KINGDOM \| United Kingdom Building Services [Member]
Schedule of Remaining Performance Obligations [Line Items]
Remaining performance obligations	$ 211,828
Remaining performance obligations, percent	2.00%

EMCOR Group, Inc. 10-Q