Changes in Shareholders' Equity (Schedule of Activity in Shareholders' Equity) (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Oct. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period		$ 877,605	$ 819,865	$ 819,865
Net income		28,075	27,609
Compensation and benefits paid or payable in shares		745	(13)
Options exercised		7	128
Shares issued to Directors'		0	0
Purchase of Treasury shares		(43,937)
Cumulative translation adjustments		(1,674)	(16,165)
Pension and postretirement liability adjustments		74	509
Derivative valuation adjustment		10,018	752
Balance at end of the period		$ 864,252	$ 826,211	$ 877,605
Dividends declared per share, Class A and Class B (in dollars per share)		$ 0.21	$ 0.20
Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared		$ (6,661)	$ (6,150)
Dividends declared per share, Class A and Class B (in dollars per share)		$ 0.21	$ 0.20
Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the period (in shares)		104
Dividends declared		$ 0	$ (324)
Balance at the end of the period (in shares)		0		104
Dividends declared per share, Class A and Class B (in dollars per share)		$ 0.21	$ 0.20
Common Stock | Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the period (in shares)		40,760,000	39,115,000	39,115,000
Balance at beginning of the period		$ 41	$ 39	$ 39
Compensation and benefits paid or payable in shares (in shares)		21,000	20,000
Options exercised (in shares)		0
Balance at the end of the period (in shares)		40,781,000	39,141,000	40,760,000
Balance at end of the period		$ 41	$ 39	$ 41
Common Stock | Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the period (in shares)		0	1,618,000	1,618,000
Balance at beginning of the period		$ 0	$ 2	$ 2
Balance at the end of the period (in shares)		0	1,618,000	0
Balance at end of the period		$ 0	$ 2	$ 0
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period		436,996	433,696	433,696
Compensation and benefits paid or payable in shares		745	(13)
Options exercised		7	128
Balance at end of the period		437,748	433,811	436,996
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period		863,057	770,746	770,746
Net income		27,737	27,582
Balance at end of the period		884,133	791,854	863,057
Retained earnings | Common Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared		(6,661)	(6,150)
Retained earnings | Common Class B
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends declared		0	(324)
Accumulated items of other comprehensive income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period		(145,984)	(132,408)	(132,408)
Cumulative translation adjustments		(1,730)	(15,955)
Pension and postretirement liability adjustments		74	509
Derivative valuation adjustment		10,018	752
Balance at end of the period		$ (137,622)	$ (147,102)	$ (145,984)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at the beginning of the period (in shares)		8,665,000	8,391,000	8,391,000
Balance at beginning of the period		$ (280,143)	$ (256,009)	$ (256,009)
Purchase of Treasury shares (in shares)		514,686		285,286
Purchase of Treasury shares	$ 200,000	$ (43,937)		$ (24,400)
Balance at the end of the period (in shares)		9,180,000	8,391,000	8,665,000
Balance at end of the period		$ (324,080)	$ (256,009)	$ (280,143)
Noncontrolling Interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of the period		3,638	3,799	3,799
Net income		338	27
Cumulative translation adjustments		56	(210)
Balance at end of the period		$ 4,032	$ 3,616	$ 3,638