Fair value measurements - Cash payments required for deferred premium contracts (Details) $ in Thousands	Sep. 30, 2019 USD ($)
Fair Value Disclosures [Abstract]
Remaining 2019	$ 1,399
2020	477
Total	$ 1,876

Derivative Financial Instrument, Deferred Premium, Future Payments Due, Remaining Fiscal Year

No definition available.

Name:	lpi_DerivativeFinancialInstrumentDeferredPremiumFuturePaymentsDueRemainingFiscalYear
Namespace Prefix:	lpi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant