Fair Value Measurements (Narrative) (Detail) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 Grade
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial instruments using fair value measurement option | $	$ 0
Commodity Swaps And Options [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Weighted Average Risk Grade | Grade		14.0
Weighted average loss severity in the event of default on commodity swaps		10.00%