Condensed Consolidated Statements Of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balances, shares at Dec. 31, 2018		41,357
Shares repurchased and retired, shares		(4,590)
Stock options exercised, shares		65
Vesting of restricted stock units, shares		252
Shares withheld for taxes, shares		(48)
Balances, shares at Sep. 30, 2019		37,036
Beginning Balances, value at Dec. 31, 2018	$ 1,132,225	$ 4,136	$ 554,939	$ 584,274	$ (11,124)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	8,461	0	8,461	0	0
Shares repurchased and retired, value	(118,350)	(459)	(51,004)	(66,887)	0
Stock options exercised, value	1,350	6	1,344	0	0
Vesting of restricted stock units, value	0	25	(25)	0	0
Shares withheld for taxes, value	(1,318)	(4)	(1,314)	0	0
Dividends declared	(17,083)	0	0	(17,083)	0
Net income	30,356	0	0	30,356	0
Other comprehensive income (loss)	(6,869)	0	0	0	(6,869)
Ending Balances, value at Sep. 30, 2019	1,028,772	$ 3,704	512,401	530,660	(17,993)
Balances, shares at Jun. 30, 2019		37,679
Shares repurchased and retired, shares		(682)
Stock options exercised, shares		32
Vesting of restricted stock units, shares		10
Shares withheld for taxes, shares		(3)
Balances, shares at Sep. 30, 2019		37,036
Beginning Balances, value at Jun. 30, 2019	1,045,050	$ 3,768	516,663	539,743	(15,124)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	2,741	0	2,741	0	0
Shares repurchased and retired, value	(18,311)	(68)	(7,580)	(10,663)	0
Stock options exercised, value	657	3	654	0	0
Vesting of restricted stock units, value	0	1	(1)	0	0
Shares withheld for taxes, value	(76)	0	(76)	0	0
Dividends declared	(5,556)	0	0	(5,556)	0
Net income	7,136	0	0	7,136	0
Other comprehensive income (loss)	(2,869)	0	0	0	(2,869)
Ending Balances, value at Sep. 30, 2019	$ 1,028,772	$ 3,704	512,401	530,660	(17,993)
Balances, shares at Dec. 31, 2019	36,957	36,957
Shares repurchased and retired, shares		(724)
Stock options exercised, shares		17
Vesting of restricted stock units, shares		301
Shares withheld for taxes, shares		(77)
Balances, shares at Sep. 30, 2020	36,474	36,474
Beginning Balances, value at Dec. 31, 2019	$ 1,014,832	$ 3,696	512,019	515,876	(16,759)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	9,464	0	9,464	0	0
Shares repurchased and retired, value	(19,329)	(72)	(8,048)	(11,209)	0
Stock options exercised, value	371	2	369	0	0
Vesting of restricted stock units, value	0	30	(30)	0	0
Shares withheld for taxes, value	(1,913)	(8)	(1,905)	0	0
Dividends declared	(17,503)	0	0	(17,503)	0
Net income	6,360	0	0	6,360	0
Other comprehensive income (loss)	(1,955)	0	0	0	(1,955)
Ending Balances, value at Sep. 30, 2020	$ 990,327	$ 3,648	511,869	493,524	(18,714)
Balances, shares at Jun. 30, 2020		36,461
Stock options exercised, shares		0
Vesting of restricted stock units, shares		18
Shares withheld for taxes, shares		(5)
Balances, shares at Sep. 30, 2020	36,474	36,474
Beginning Balances, value at Jun. 30, 2020	$ 984,360	$ 3,647	508,555	493,450	(21,292)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	3,420	0	3,420	0	0
Stock options exercised, value	7	0	7	0	0
Vesting of restricted stock units, value	0	2	(2)	0	0
Shares withheld for taxes, value	(112)	(1)	(111)	0	0
Dividends declared	(5,841)	0	0	(5,841)	0
Net income	5,915	0	0	5,915	0
Other comprehensive income (loss)	2,578	0	0	0	2,578
Ending Balances, value at Sep. 30, 2020	$ 990,327	$ 3,648	$ 511,869	$ 493,524	$ (18,714)