Equity and Noncontrolling Interest - Changes in Equity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Beginning Balance	$ 1,329,453	$ 1,162,032	$ 1,320,914	$ 1,242,366
Net income (loss)	33,600	(7,722)	72,232	(36,066)
Amounts reported in other comprehensive income (loss)	17,293	12,261	(9,339)	(31,225)
Dividends	(7,062)	(6,853)	(14,124)	(13,687)
Acquisition of noncontrolling interest				(1,047)
Distributions to noncontrolling affiliate shareholders				(751)
Share issuance and equity-based compensation plans	2,117	7,623	5,718	8,662
Ending Balance	1,375,401	1,167,341	1,375,401	1,167,341
Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				(911)
Adjusted Balance [Member]
Beginning Balance				1,241,455
Common Stock [Member]
Beginning Balance	17,875	17,752	17,851	17,735
Net income (loss)	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends	0	0	0	0
Acquisition of noncontrolling interest				0
Distributions to noncontrolling affiliate shareholders				0
Share issuance and equity-based compensation plans	3	48	27	65
Ending Balance	17,878	17,800	17,878	17,800
Common Stock [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				0
Common Stock [Member] | Adjusted Balance [Member]
Beginning Balance				17,735
Capital in Excess of Par Value [Member]
Beginning Balance	908,748	888,533	905,171	888,218
Net income (loss)	0	0	0	0
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends	0	0	0	0
Acquisition of noncontrolling interest				(707)
Distributions to noncontrolling affiliate shareholders				0
Share issuance and equity-based compensation plans	2,114	7,575	5,691	8,597
Ending Balance	910,862	896,108	910,862	896,108
Capital in Excess of Par Value [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				0
Capital in Excess of Par Value [Member] | Adjusted Balance [Member]
Beginning Balance				888,218
Retained Earnings [Member]
Beginning Balance	455,493	376,853	423,940	412,979
Net income (loss)	33,570	(7,735)	72,185	(36,116)
Amounts reported in other comprehensive income (loss)	0	0	0	0
Dividends	(7,062)	(6,853)	(14,124)	(13,687)
Acquisition of noncontrolling interest				0
Distributions to noncontrolling affiliate shareholders				0
Share issuance and equity-based compensation plans	0	0	0	0
Ending Balance	482,001	362,265	482,001	362,265
Retained Earnings [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				(911)
Retained Earnings [Member] | Adjusted Balance [Member]
Beginning Balance				412,068
Accumulated Other Comprehensive Income (Loss) [Member]
Beginning Balance	(53,228)	(121,524)	(26,598)	(78,170)
Net income (loss)	0	0	0	0
Amounts reported in other comprehensive income (loss)	17,285	12,260	(9,345)	(31,094)
Dividends	0	0	0	0
Acquisition of noncontrolling interest				0
Distributions to noncontrolling affiliate shareholders				0
Share issuance and equity-based compensation plans	0	0	0	0
Ending Balance	(35,943)	(109,264)	(35,943)	(109,264)
Accumulated Other Comprehensive Income (Loss) [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				0
Accumulated Other Comprehensive Income (Loss) [Member] | Adjusted Balance [Member]
Beginning Balance				(78,170)
Noncontrolling Interest [Member]
Beginning Balance	565	418	550	1,604
Net income (loss)	30	13	47	50
Amounts reported in other comprehensive income (loss)	8	1	6	(131)
Dividends	0	0	0	0
Acquisition of noncontrolling interest				(340)
Distributions to noncontrolling affiliate shareholders				(751)
Share issuance and equity-based compensation plans	0	0	0	0
Ending Balance	$ 603	$ 432	$ 603	432
Noncontrolling Interest [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
Beginning Balance				0
Noncontrolling Interest [Member] | Adjusted Balance [Member]
Beginning Balance				$ 1,604