Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accumulated depreciation on operating properties	$ 1,197,310	$ 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)	154,336,492	154,019,214
Common stock, shares outstanding (in shares)	151,774,468	151,457,190
Treasury stock, shares (in shares)	2,562,024	2,562,024