Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to the Company	$ 32,354	$ 34,054	$ 41,463	$ 63,244
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Weighted average number of shares outstanding, Basic (in shares)	32,328	32,299	32,320	32,286
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Stock options	8	12	8	12
Weighted average number of shares used in calculating diluted net income per share	32,336	32,311	32,328	32,298
Average market price of common stock used for calculation of dilutive shares (in dollars per share)	$ 54.08	$ 74.86	$ 59.73	$ 73.08
Earnings Per Share, Basic and Diluted [Abstract]
Earnings per share attributable to Company shareholders - Basic (in dollars per share)	1.00	1.05	1.28	1.96
Earnings per share attributable to Company shareholders - Diluted (in dollars per share)	$ 1.00	$ 1.05	$ 1.28	$ 1.96