Long-Term Debt (Details) - Line of Credit |
6 Months Ended |
|---|---|
|
Jun. 30, 2017
USD ($)
| |
| Revolving Credit Facility | |
| Debt Instrument [Line Items] | |
| Current borrowing capacity | $ 350,000,000 |
| Remaining borrowing capacity | 314,100,000 |
| Outstanding line of credit | $ 35,000,000 |
| 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 |