Investment in Affiliates (Detail)
|
Apr. 30, 2016 |
| Boyles Bros Servicios Tecnicos Geologicos S.A. [Member] | Percentage Owned Directly [Member] | Panama [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Boytec, S.A. [Member] | Percentage Owned Indirectly [Member] | Panama [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Boytec Sondajes de Mexico, S.A. de C.V. [Member] | Percentage Owned Indirectly [Member] | Mexico [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Sondajes Colombia, S.A. [Member] | Percentage Owned Indirectly [Member] | Colombia [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Mining Drilling Fluids [Member] | Percentage Owned Indirectly [Member] | Panama [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
25.00%
|
| Plantel Industrial S.A. [Member] | Percentage Owned Indirectly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Christensen Chile, S.A. [Member] | Percentage Owned Directly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Christensen Commercial, S.A. [Member] | Percentage Owned Directly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Christensen Commercial, S.A. [Member] | Percentage Owned Directly [Member] | Peru [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
35.38%
|
| Geotec Boyles Bros., S.A. [Member] | Percentage Owned Directly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Centro Internacional de Formacion S.A. [Member] | Percentage Owned Indirectly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
50.00%
|
| Geoestrella S.A. [Member] | Percentage Owned Indirectly [Member] | Chile [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
25.00%
|
| Diamantina Christensen Trading [Member] | Percentage Owned Directly [Member] | Panama [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
42.69%
|
| Geotec, S.A. [Member] | Percentage Owned Directly [Member] | Peru [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
35.38%
|
| Boyles Bros., Diamantina, S.A. [Member] | Percentage Owned Directly [Member] | Peru [Member] |
|
| Schedule Of Equity Method Investments [Line Items] |
|
| Percentage Owned |
29.49%
|