Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Current assets:
Allowance for doubtful accounts	$ 78,776	$ 74,336
Contract asset, allowance for doubtful accounts	3,704	2,393
Accumulated depreciation on property, plant and equipment	1,150,876	1,191,823
Other assets, allowance for credit loss	$ 67,968	$ 67,696
Shareholders’ equity:
Common shares, par value (in dollars per share)	$ 1.25	$ 1.25
Common shares, shares authorized (in shares)	305,000	305,000
Common shares, shares issued (in shares)	176,793	176,793
Treasury shares, shares (in shares)	46,377	46,794