Changes in Shareholders' Equity (Schedule of Activity in Shareholders' Equity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended		12 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Oct. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period	$ 864,252	$ 877,605	$ 826,211	$ 819,865	$ 877,605	$ 819,865	$ 819,865
Net income	39,369	28,075	31,440	27,609	67,444	59,050
Compensation and benefits paid or payable in shares	902	745	692	(13)
Options exercised		7	21	128
Shares issued to Directors'	1,085	0	947	0
Purchase of Treasury shares	(41,128)	(43,937)
Cumulative translation adjustments	(39,752)	(1,674)	13,957	(16,165)
Pension and postretirement liability adjustments	234	74	(130)	509
Derivative valuation adjustment	3,349	10,018	1,394	752
Balance at end of the period	$ 821,782	864,252	$ 868,059	826,211	$ 821,782	$ 868,059	$ 877,605
Dividends declared per share, Class A and Class B (in dollars per share)	$ 0.21		$ 0.20		$ 0.42	$ 0.40
Stock repurchase program, authorized amount								$ 200,000
Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared	$ (6,529)	$ (6,661)	$ (6,150)	$ (6,150)
Dividends declared per share, Class A and Class B (in dollars per share)	$ 0.21	$ 0.21	$ 0.20	$ 0.20
Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, balance at the beginning of the period (in shares)		104			104
Dividends declared			$ (323)	$ (324)
Common stock, balance at the end of the period (in shares)	0				0		104
Dividends declared per share, Class A and Class B (in dollars per share)	$ 0.21	$ 0.21	$ 0.20	$ 0.20
Common Stock | Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, balance at the beginning of the period (in shares)	40,781,000	40,760,000	39,141,000	39,115,000	40,760,000	39,115,000	39,115,000
Balance at beginning of the period	$ 41	$ 41	$ 39	$ 39	$ 41	$ 39	$ 39
Compensation and benefits paid or payable in shares (in shares)	4,000	21,000		20,000
Options exercised (in shares)			1,000	6,000
Common stock, balance at the end of the period (in shares)	40,785,000	40,781,000	39,142,000	39,141,000	40,785,000	39,142,000	40,760,000
Balance at end of the period	$ 41	$ 41	$ 39	$ 39	$ 41	$ 39	$ 41
Common Stock | Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, balance at the beginning of the period (in shares)	0	0	1,618,000	1,618,000	0	1,618,000	1,618,000
Balance at beginning of the period	$ 0	$ 0	$ 2	$ 2	$ 0	$ 2	$ 2
Common stock, balance at the end of the period (in shares)	0	0	1,618,000	1,618,000	0	1,618,000	0
Balance at end of the period	$ 0	$ 0	$ 2	$ 2	$ 0	$ 2	$ 0
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period	437,748	436,996	433,811	433,696	436,996	433,696	433,696
Net income			0
Compensation and benefits paid or payable in shares	902	745	692	(13)
Options exercised		7	21	128
Shares issued to Directors'	800		706
Balance at end of the period	439,450	437,748	435,230	433,811	439,450	435,230	436,996
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period	884,133	863,057	791,854	770,746	863,057	770,746	770,746
Net income	39,201	27,737	31,397	27,582
Balance at end of the period	916,805	884,133	816,778	791,854	916,805	816,778	863,057
Retained earnings | Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared	(6,529)	(6,661)	(6,150)	(6,150)
Retained earnings | Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared			(323)	(324)
Accumulated items of other comprehensive income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period	(137,622)	(145,984)	(147,102)	(132,408)	(145,984)	(132,408)	(132,408)
Cumulative translation adjustments	(39,661)	(1,730)	13,774	(15,955)
Pension and postretirement liability adjustments	234	74	(130)	509
Derivative valuation adjustment	3,349	10,018	1,394	752
Balance at end of the period	$ (173,700)	$ (137,622)	$ (132,064)	$ (147,102)	$ (173,700)	$ (132,064)	$ (145,984)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock, balance at the beginning of the period (in shares)	9,180,000	8,665,000	8,391,000	8,391,000	8,665,000	8,391,000	8,391,000
Balance at beginning of the period	$ (324,080)	$ (280,143)	$ (256,009)	$ (256,009)	$ (280,143)	$ (256,009)	$ (256,009)
Shares issued to Directors' (in shares)	(13,000)		(11,000)
Shares issued to Directors'	$ 285		$ 241
Purchase of Treasury shares (in shares)	508,000	515,000			1,022,717		285,286
Purchase of Treasury shares	$ (41,128)	$ (43,937)			$ (85,100)		$ (24,400)
Treasury stock, balance at the end of the period (in shares)	9,675,000	9,180,000	8,380,000	8,391,000	9,675,000	8,380,000	8,665,000
Balance at end of the period	$ (364,923)	$ (324,080)	$ (255,768)	$ (256,009)	$ (364,923)	$ (255,768)	$ (280,143)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period	4,032	3,638	3,616	3,799	3,638	3,799	3,799
Net income	168	338	43	27
Cumulative translation adjustments	(91)	56	183	(210)
Balance at end of the period	$ 4,109	$ 4,032	$ 3,842	$ 3,616	$ 4,109	$ 3,842	$ 3,638