Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to the Company	$ 29,589	$ 40,009	$ 71,052	$ 103,253
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average number of shares outstanding, Basic (in shares)	32,337	32,306	32,326	32,293
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Stock options	7	11	7	12
Weighted average number of shares used in calculating diluted net income per share	32,344	32,317	32,333	32,305
Average market price of common stock used for calculation of dilutive shares (in dollars per share)	$ 51.81	$ 82.99	$ 57.05	$ 76.45
Earnings Per Share, Basic and Diluted [Abstract]
Earnings per share attributable to Company shareholders - Basic (in dollars per share)	0.92	1.24	2.20	3.20
Earnings per share attributable to Company shareholders - Diluted (in dollars per share)	$ 0.91	$ 1.24	$ 2.20	$ 3.20