Financial Instruments and Risk Management (Carrying Value of Assets and Liabilities Recorded at Fair Value on Recurring Basis) (Details) - Fair Value - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets:
Assets	$ 0	$ 4,280
Liabilities:
Liabilities	647,555	472,528
Commodity collars
Assets:
Derivative assets	0	4,280
Liabilities:
Derivative liability	146,780	19,533
Commodity swaps
Liabilities:
Derivative liability	239,382	239,882
Contingent consideration
Liabilities:
Contingent consideration	244,226	196,151
Nonqualified employee savings plan
Liabilities:
Nonqualified employee savings plan	17,167	16,962
Level 1
Assets:
Assets	0	0
Liabilities:
Liabilities	17,167	16,962
Level 1 | Commodity collars
Assets:
Derivative assets	0	0
Liabilities:
Derivative liability	0	0
Level 1 | Commodity swaps
Liabilities:
Derivative liability	0	0
Level 1 | Contingent consideration
Liabilities:
Contingent consideration	0	0
Level 1 | Nonqualified employee savings plan
Liabilities:
Nonqualified employee savings plan	17,167	16,962
Level 2
Assets:
Assets	0	4,280
Liabilities:
Liabilities	386,162	259,415
Level 2 | Commodity collars
Assets:
Derivative assets	0	4,280
Liabilities:
Derivative liability	146,780	19,533
Level 2 | Commodity swaps
Liabilities:
Derivative liability	239,382	239,882
Level 2 | Contingent consideration
Liabilities:
Contingent consideration	0	0
Level 2 | Nonqualified employee savings plan
Liabilities:
Nonqualified employee savings plan	0	0
Level 3
Assets:
Assets	0	0
Liabilities:
Liabilities	244,226	196,151
Level 3 | Commodity collars
Assets:
Derivative assets	0	0
Liabilities:
Derivative liability	0	0
Level 3 | Commodity swaps
Liabilities:
Derivative liability	0	0
Level 3 | Contingent consideration
Liabilities:
Contingent consideration	244,226	196,151
Level 3 | Nonqualified employee savings plan
Liabilities:
Nonqualified employee savings plan	$ 0	$ 0