XML 37 R25.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Interest Expense (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2017
Interest and Debt Expense [Abstract] |
Schedule Of Interest Expense | The following tables present the components of interest expense:
| For the Three Months Ended September 30, |  | For the Nine Months Ended September 30,
| 2016 |  | 2017 |  | 2016 |  | 2017
| (Dollars in thousands)
Interest incurred on debt | $ | 5,306 |  |  | $ | 6,097 |  |  | $ | 15,020 |  |  | $ | 18,183 |
Accretion of fair value adjustment on Senior Notes | 1,581 |  |  | 1,618 |  |  | 4,715 |  |  | 4,826 |
Amortization of debt issuance costs | 77 |  |  | 77 |  |  | 125 |  |  | 231 |
Total interest expense | $ | 6,964 |  |  | $ | 7,792 |  |  | $ | 19,860 |  |  | $ | 23,240 |

X
- Definition Schedule of Interest Expense [Table Text Block] + References No definition available. + Details
Name: | gti_ScheduleOfInterestExpenseTableTextBlock
Namespace Prefix: | gti_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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