Long-Term Debt (Details) - Line of Credit - USD ($) |
9 Months Ended | |
|---|---|---|
Sep. 30, 2017 |
Nov. 02, 2017 |
|
| Revolving Credit Facility | ||
| Debt Instrument [Line Items] | ||
| Current borrowing capacity | $ 350,000,000 | |
| Remaining borrowing capacity | 184,100,000 | |
| Outstanding line of credit | $ 165,000,000 | |
| Automatic decrease in borrowing base | 25.00% | |
| Covenant compliance, minimum required current ratio | 100.00% | |
| Covenant compliance, maximum allowable leverage ratio | 400.00% | |
| Letter of Credit | ||
| Debt Instrument [Line Items] | ||
| Maximum borrowing capacity | $ 15,000,000.0 | |
| Letters of credit outstanding | $ 900,000 | |
| Subsequent Event | Revolving Credit Facility | ||
| Debt Instrument [Line Items] | ||
| Current borrowing capacity | $ 575,000,000 |