Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Common stock [Member]	Additional paid-in capital ("APIC") [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss) [Member]	Non-controlling interest ("NCI") [Member]	Contingently Redeemable Performance Share Units [Member]	Total
Balance at Dec. 31, 2018	$ 181,780	$ 56,885	$ 648,255	$ (56,277)	$ 5,067	$ 923	$ 835,710
Balance, shares at Dec. 31, 2018	108,682,030
Net income			18,164		8		18,172
Other comprehensive loss				(1,622)	(12)		(1,634)
Comprehensive income			18,164	(1,622)	(4)		16,538
Stock option exercises	$ 2,478	(850)					1,628
Stock option exercises, shares	82,926
Issuance of common stock related to vesting of share units	$ 5,039	(10,064)					(5,025)
Issuance of common stock related to vesting of share units, shares	193,950
Stock option compensation expense		1,539					1,539
Equity-classified PSU expense		2,322				46	2,322
Equity-classified PSU dividend equivalents		222	(237)			15	(15)
Cash dividends paid			(19,568)				(19,568)
Balance at Mar. 31, 2019	$ 189,297	50,054	646,614	(57,899)	5,063	$ 984	833,129
Balance, shares at Mar. 31, 2019	108,958,906
Balance at Dec. 31, 2019	$ 194,771	52,110	714,051	(59,099)	5,154		906,987
Balance, shares at Dec. 31, 2019	109,337,781
Net income			22,809		20		22,829
Other comprehensive loss				(15,860)	(8)		(15,868)
Comprehensive income			22,809	(15,860)	12		6,961
Stock option exercises	$ 8,684	(1,630)					$ 7,054
Stock option exercises, shares	247,446						247,446
Issuance of common stock related to vesting of share units	$ 3,516	(7,445)					$ (3,929)
Issuance of common stock related to vesting of share units, shares	138,824
Stock option compensation expense		1,187					1,187
Equity-classified PSU expense		1,786					1,786
Equity-classified PSU dividend equivalents		139	(139)
Cash dividends paid			(21,905)				(21,905)
Shares repurchased	$ (53,170)						(53,170)
Shares repurchased, shares	(1,525,312)
Balance at Mar. 31, 2020	$ 153,801	$ 46,147	$ 714,816	$ (74,959)	$ 5,166		$ 844,971
Balance, shares at Mar. 31, 2020	108,198,739