Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital from Treasury Stock Transactions	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income (Loss), net of tax
Balance, beginning of period at Dec. 31, 2018	$ 857,121	$ 367,252	$ 0	$ 791,823	$ (287,337)	$ (14,617)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	54,546			54,546
Other Comprehensive Income (Loss), net of tax	7,664					7,664
Stock Award Activity	7,110	7,110		(11,830)	11,830
Dividends Declared	(27,217)			(27,217)
Purchase of Treasury Stock	(1,485)				(1,485)
Balance, end of period at Mar. 31, 2019	897,739	374,362	0	807,322	(276,992)	(6,953)
Temporary equity, beginning balance at Dec. 31, 2018	182,513
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	65
Other Comprehensive Income (Loss), net of tax	3,714
Subscriptions—Redeemable Noncontrolling Interest Holders	42
Stock Award Activity	2,126
Distributions to Noncontrolling Interest in Subsidiaries	(2,260)
Temporary equity, ending balance at Mar. 31, 2019	186,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	62,724			62,724
Other Comprehensive Income (Loss), net of tax	(9,539)					(9,539)
Stock Award Activity	6,240	6,069	103		68
Dividends Declared	(27,323)			(27,323)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	(16,604)			(16,604)
Purchase of Treasury Stock	(709)				(709)
Balance, end of period at Jun. 30, 2019	912,528	380,431	103	826,119	(277,633)	(16,492)
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	1,116
Other Comprehensive Income (Loss), net of tax	(4,600)
Subscriptions—Redeemable Noncontrolling Interest Holders	1,822
Stock Award Activity	1,773
Distributions to Noncontrolling Interest in Subsidiaries	(541)
Business Acquisition	(386)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	16,604
Temporary equity, ending balance at Jun. 30, 2019	201,988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	72,962			72,962
Other Comprehensive Income (Loss), net of tax	(11,795)					(11,795)
Stock Award Activity	5,969	5,947	1		21
Dividends Declared	(27,307)			(27,307)
Purchase of Treasury Stock	(1,860)				(1,860)
Balance, end of period at Sep. 30, 2019	950,497	386,378	$ 104	871,774	(279,472)	(28,287)
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	623
Other Comprehensive Income (Loss), net of tax	(5,544)
Subscriptions—Redeemable Noncontrolling Interest Holders	687
Stock Award Activity	2,125
Distributions to Noncontrolling Interest in Subsidiaries	(387)
Temporary equity, ending balance at Sep. 30, 2019	199,492
Balance, beginning of period at Dec. 31, 2019	1,041,280	392,210		930,351	(281,032)	(249)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	64,178			64,178
Other Comprehensive Income (Loss), net of tax	(24,859)					(24,859)
Stock Award Activity	7,467	7,467		(16,146)	16,146
Dividends Declared	(27,304)			(27,304)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	(1,870)			(1,870)
Purchase of Treasury Stock	(15,959)				(15,959)
Balance, end of period at Mar. 31, 2020	1,042,933	399,677		949,209	(280,845)	(25,108)
Temporary equity, beginning balance at Dec. 31, 2019	212,086
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	(913)
Other Comprehensive Income (Loss), net of tax	(11,454)
Subscriptions—Redeemable Noncontrolling Interest Holders	5,577
Consolidation (Deconsolidation)	(4,019)
Stock Award Activity	2,153
Distributions to Noncontrolling Interest in Subsidiaries	(6,039)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	1,870
Temporary equity, ending balance at Mar. 31, 2020	199,261
Balance, beginning of period at Dec. 31, 2019	1,041,280	392,210		930,351	(281,032)	(249)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Purchase of Treasury Stock	(54,100)
Balance, end of period at Sep. 30, 2020	1,151,576	412,414		1,066,842	(318,098)	(9,582)
Temporary equity, beginning balance at Dec. 31, 2019	212,086
Temporary equity, ending balance at Sep. 30, 2020	214,301
Balance, beginning of period at Mar. 31, 2020	1,042,933	399,677		949,209	(280,845)	(25,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	81,196			81,196
Other Comprehensive Income (Loss), net of tax	(713)					(713)
Stock Award Activity	6,607	6,456		(678)	829
Dividends Declared	(27,243)			(27,243)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	2,013			2,013
Purchase of Treasury Stock	(18,126)				(18,126)
Balance, end of period at Jun. 30, 2020	1,086,667	406,133		1,004,497	(298,142)	(25,821)
Temporary equity, beginning balance at Mar. 31, 2020	199,261
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	3,605
Other Comprehensive Income (Loss), net of tax	(435)
Subscriptions—Redeemable Noncontrolling Interest Holders	6,225
Stock Award Activity	2,087
Distributions to Noncontrolling Interest in Subsidiaries	(4,058)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	(2,013)
Temporary equity, ending balance at Jun. 30, 2020	204,672
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	85,822			85,822
Other Comprehensive Income (Loss), net of tax	16,239					16,239
Stock Award Activity	6,348	6,281			67
Dividends Declared	(27,044)			(27,044)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	3,567			3,567
Purchase of Treasury Stock	(20,023)				(20,023)
Balance, end of period at Sep. 30, 2020	1,151,576	$ 412,414		$ 1,066,842	$ (318,098)	$ (9,582)
Increase (Decrease) in Temporary Equity [Roll Forward]
Net Income (Loss)	862
Other Comprehensive Income (Loss), net of tax	7,316
Subscriptions—Redeemable Noncontrolling Interest Holders	3,212
Stock Award Activity	2,164
Distributions to Noncontrolling Interest in Subsidiaries	(358)
Change in Estimated Redemption Value of Redeemable Noncontrolling Interests	(3,567)
Temporary equity, ending balance at Sep. 30, 2020	$ 214,301