Employee Benefit Plans (Details) - USD ($)	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Multiemployer Pension Plans
Total contributions made	$ 54,724	$ 48,709	$ 46,011
Contributions to other multiemployer plans	$ 19,827	$ 20,378	16,606
Boilermaker-Blacksmith National Pension Trust [Member]
Multiemployer Plans [Line Items]
Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date, Description	Described below (1)
Multiemployer Pension Plans
EIN/Pension Plan Number	48-6168020/001
Multiemployer Plans, Certified Zone Status, Description	Yellow	Described below (2)
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 8,525	$ 7,098	7,658
Multiemployer Plan, Surcharge	No
Joint Pension Fund Local Union One Six Four Ibew [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-6031199/001
Multiemployer Plans, Certified Zone Status, Description	Yellow	Described below (2)
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 2,391	$ 2,709	2,635
Multiemployer Plan, Surcharge	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2021
Joint Pension Fund Local Union Number One Zero Two [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-1615726/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 2,489	$ 2,392	3,063
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2019
IBEW Local Four Five Six Pension Plan [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-6238995/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 6,005	$ 2,777	1,168
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2021
Local 351 IBEW Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	22-3417366/001
Multiemployer Plans, Certified Zone Status, Description	Green	Green
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 1,187	$ 2,796	5,018
Multiemployer Plan, Surcharge	No
Expiration Date of Collective-Bargaining Agreement	Dec. 04, 2021
Steamfitters Local Union Number Four Two Zero Pension Plan [Member] [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	23-2004424/001
Pension Protection Act Zone Status	Red	Red
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 1,558	$ 2,234	1,265
Surcharge Imposed	Yes
Expiration Date of Collective-Bargaining Agreement	Apr. 30, 2020
IBEW Local Union Nine Eight Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	23-1990722/001
Multiemployer Plans, Certified Zone Status, Description	Red	Described below (2)
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 1,106	$ 1,519	1,653
Multiemployer Plan, Surcharge	Yes
Expiration Date of Collective-Bargaining Agreement	May 29, 2020
Indiana Laborers Pension Fund [Domain]
Multiemployer Pension Plans
EIN/Pension Plan Number	35-6027150/001
Multiemployer Plans, Certified Zone Status, Description	Described below (2)	Described below (2)
FIP/RP Status Pending or Implemented	Implemented
Total contributions made	$ 3,542	$ 2,458	2,320
Multiemployer Plan, Surcharge	Described below (2)
Expiration Date of Collective-Bargaining Agreement	May 31, 2019
Ironworkers Mid-America Pension Plan [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	36-6488227/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 4,412	$ 1,785	2,248
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2019
Plumbers and Pipefitters Local Union Seven Four Pension Fund [Member]
Multiemployer Pension Plans
FIP/RP Status Pending or Implemented	Implemented
Pipefitters Retirement Fund Local Five Nine Seven [Member]
Multiemployer Pension Plans
EIN/Pension Plan Number	62-6105084/001
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending or Implemented	NA
Total contributions made	$ 3,682	$ 2,563	$ 2,377
Surcharge Imposed	No
Expiration Date of Collective-Bargaining Agreement	May 31, 2019

Contributions to other multiemployer plans.

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Multiemployer plans number.

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Indicate the multiemployer plan's certified zone status as currently required by the Pension Protection Act of 2006 or a subsequent amendment thereof. The zone status categories are red (critical status), orange (seriously endangered), yellow (endangered), and green (none of the above). The acceptable values are "red", "orange", "yellow", "green", "other", and "NA". A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Expiration date of the collective bargaining arrangement requiring contributions to the multiemployer plan, in CCYY-MM-DD format. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Description of the significant collective-bargaining arrangements within the range of expiration dates for collective-bargaining arrangements requiring contributions to a multiemployer plan as well as other information to help investors understand the significance of the collective-bargaining agreements and when they expire. A multiemployer plan is a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

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Indicate whether a funding improvement plan or rehabilitation plan has been implemented or is pending for a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "pending", "implemented", "other", and "NA".

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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.

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Indicate whether the employer paid a surcharge to the pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. The acceptable values are "no", "yes", and "NA".

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