Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accumulated depreciation on operating properties	$ 1,131,555	$ 1,079,662
Common stock, par value (in usd per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	300,000,000	300,000,000
Common stock, shares issued (in shares)	154,255,888	154,019,214
Common stock, shares outstanding (in shares)	151,693,864	151,457,190
Treasury stock, shares (in shares)	2,562,024	2,562,024