Condensed Consolidated Statements of Equity - USD ($) $ in Thousands		Total		Common Shares	Additional Paid-in Capital	Treasury Shares	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Noncontrolling Interests
Beginning Balance at Dec. 31, 2017		$ 822,899		$ 96	$ 224,622	$ (40,312)	$ (2,700)	$ 633,496	$ 7,697
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		19,431						19,829	(398)
Other comprehensive income (loss)		(2,647)	[1]				(2,647)
Amounts reclassified from accumulated other comprehensive loss		(2,273)
Cash received from noncontrolling interest		21,806							21,806
Adoption of accounting standard, net of income tax of $2,869		(8,441)						(8,441)
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax		3,268			(1,363)	4,631
Dividends declared per common share		(9,326)						(9,326)
Restricted share award dividend equivalents		0				120		(120)
Ending Balance at Jun. 30, 2018		846,990		96	223,259	(35,561)	(5,347)	635,438	29,105
Beginning Balance at Mar. 31, 2018		822,757		96	221,990	(36,028)	(3,988)	618,572	22,115
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		21,413						21,529	(116)
Other comprehensive income (loss)		(1,359)	[1]				(1,359)
Amounts reclassified from accumulated other comprehensive loss		(1,123)
Cash received from noncontrolling interest		7,106							7,106
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax		1,736			1,269	467
Dividends declared per common share		(4,663)						(4,663)
Ending Balance at Jun. 30, 2018		846,990		96	223,259	(35,561)	(5,347)	635,438	29,105
Beginning Balance at Dec. 31, 2018		876,764		96	224,396	(35,300)	(6,387)	647,517	46,442
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		15,263						15,895	(632)
Other comprehensive income (loss)	[1]	146
Other comprehensive income (loss)		(11,314)					(11,314)
Amounts reclassified from accumulated other comprehensive loss		11,460					11,460
Amounts reclassified from accumulated other comprehensive loss		10,574
Cash received from noncontrolling interest		4,715							4,715
Adoption of accounting standard, net of income tax of $2,869		(711)						(711)
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax		7,680			(21,018)	28,698
Dividends declared per common share		(11,059)						(11,059)
Stock awards granted due to acquisition		127,841		41	127,800
Restricted share award dividend equivalents		0			8	153		(161)
Ending Balance at Jun. 30, 2019		1,020,639		137	331,186	(6,449)	(6,241)	651,481	50,525
Beginning Balance at Mar. 31, 2019		998,286		137	324,753	(7,216)	2,474	627,136	51,002
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		29,411						29,888	(477)
Other comprehensive income (loss)	[1]	(8,715)
Other comprehensive income (loss)		(8,544)					(8,544)
Amounts reclassified from accumulated other comprehensive loss		(171)					(171)
Amounts reclassified from accumulated other comprehensive loss		(2,035)
Stock awards, stock option exercises and other shares issued to employees and directors, net of income tax		2,492			1,738	754
Dividends declared per common share		(5,530)						(5,530)
Stock awards granted due to acquisition		4,695			4,695
Restricted share award dividend equivalents		0				13		(13)
Ending Balance at Jun. 30, 2019		$ 1,020,639		$ 137	$ 331,186	$ (6,449)	$ (6,241)	$ 651,481	$ 50,525

[1] All amounts are net of tax. Amounts in parentheses indicate debits