Fresh Start Accounting - Schedule of Reconciles Reorganization Adjustments Made to Successor's Common Stock and Successor's Additional Paid-in Capital (Detail) - Reorganization Adjustments $ in Thousands	Apr. 23, 2021 USD ($)
Fresh Start Adjustment [Line Items]
Fair value of New Diamond Common Shares issued to holders of Senior Notes Claims	$ 914,236
Fair value of Emergence Warrants issued to Predecessor equity holders	20,574
Total change in Successor common stock and additional paid-in capital	934,810
Less: Par value of Successor common stock	1,453
Successor additional paid-in capital	934,800
Common Stock [Member]
Fresh Start Adjustment [Line Items]
Less: Par value of Successor common stock	$ (10)