Revenue from Contracts with Customers - Summary of Specified Types of Revenue Expected to be Recognized in Future Related to Unsatisfied Performance Obligations (Detail 1) $ in Thousands	Sep. 30, 2020 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 69,001
Mobilization and Contract Preparation Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	31,780
Capital Modification Revenue [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	19,822
Blended Rate Revenue and Other [Member]
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Revenue remaining performance obligation	$ 17,399