Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets
Property, plant and equipment, accumulated depreciation	$ 3,077,453	$ 3,028,130
Shareholders’ equity
Preferred stock, no par value (in dollars per share)	$ 0	$ 0
Preferred stock, authorized shares (in shares)	10,000,000	10,000,000
Preferred stock, issued shares (in shares)	0	0
Common stock, no par value (in dollars per share)	$ 0	$ 0
Common stock, authorized shares (in shares)	200,000,000	200,000,000
Common stock, issued shares (in shares)	109,431,346	109,311,785
Common stock, outstanding shares (in shares)	109,431,346	109,311,785