Stockholders' Equity - Schedule of Changes in Stockholders' Equity (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Balance	$ 705,103	$ 666,637	$ 714,551	$ 660,417
Net income	17,871	19,630	42,139	49,559
Other comprehensive income (loss)	3,671	(3,281)	(7,616)	(5,851)
Equity compensation	3,128	3,817	9,472	11,682
Exercise of stock options		1,464	37	1,893
Issuance of shares pursuant to vesting of restricted stock units				1
Net payments for stock issuances and buybacks	(223)	(143)	(23,247)	(24,301)
Dividends declared	(2,639)	(2,622)	(7,912)	(7,898)
Balance	726,911	685,502	726,911	685,502
Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Adjustment
Balance			(513)
Common Stock
Balance	$ 23	$ 23	$ 23	$ 22
Balance (in shares)	18,849	18,758	18,868	18,817
Exercise of stock options (in shares)		46	1	58
Issuance of shares pursuant to vesting of restricted stock units				$ 1
Issuance of shares pursuant to vesting of restricted stock units (in shares)	12	9	303	272
Net payments for stock issuances and buybacks (in shares)	(3)	(2)	(314)	(336)
Balance	$ 23	$ 23	$ 23	$ 23
Balance (in shares)	18,858	18,811	18,858	18,811
Additional Paid-in Capital
Balance	$ 354,200	$ 335,345	$ 346,795	$ 326,208
Equity compensation	3,128	3,817	9,472	11,682
Exercise of stock options		1,464	37	1,893
Net payments for stock issuances and buybacks			1,024	843
Balance	357,328	340,626	357,328	340,626
Retained Earnings
Balance	563,322	511,095	544,840	486,442
Net income	17,871	19,630	42,139	49,559
Dividends declared	(2,639)	(2,622)	(7,912)	(7,898)
Balance	578,554	528,103	578,554	528,103
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment | Revision of Prior Period, Adjustment
Balance			(513)
Treasury Stock
Balance	$ (189,011)	$ (164,705)	$ (164,963)	$ (139,704)
Balance (in shares)	4,289	3,975	3,978	3,629
Net payments for stock issuances and buybacks	$ (223)	$ (143)	$ (24,271)	$ (25,144)
Net payments for stock issuances and buybacks (in shares)	3	2	314	348
Balance	$ (189,234)	$ (164,848)	$ (189,234)	$ (164,848)
Balance (in shares)	4,292	3,977	4,292	3,977
Accumulated Other Comprehensive Loss
Balance	$ (23,431)	$ (15,121)	$ (12,144)	$ (12,551)
Other comprehensive income (loss)	3,671	(3,281)	(7,616)	(5,851)
Balance	$ (19,760)	$ (18,402)	$ (19,760)	$ (18,402)