Stockholders' Equity - Schedule of Changes in Stockholders' Equity (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Balance	$ 690,756	$ 714,551	$ 662,571	$ 714,551	$ 660,417
Net income	13,656		14,611	24,268	29,929
Other comprehensive income (loss)	(164)		(2,853)	(11,287)	(2,570)
Equity compensation	2,518		3,714	6,344	7,865
Exercise of stock options			25	37	429
Issuance of shares pursuant to vesting of restricted stock units					1
Net payments for stock issuances and buybacks	974		(8,789)	(23,024)	(24,158)
Cumulative-effect adjustment for adoption of accounting principle				(513)
Dividends declared	(2,637)		(2,642)	(5,273)	(5,276)
Balance	705,103	690,756	666,637	705,103	666,637
Common Stock
Balance	$ 23	$ 23	$ 23	$ 23	$ 22
Balance (in shares)	18,827	18,868	18,866	18,868	18,817
Exercise of stock options (in shares)			1	1	12
Issuance of shares pursuant to vesting of restricted stock units					$ 1
Issuance of shares pursuant to vesting of restricted stock units (in shares)	22		8	291	263
Net payments for stock issuances and buybacks (in shares)			(117)	(311)	(334)
Balance	$ 23	$ 23	$ 23	$ 23	$ 23
Balance (in shares)	18,849	18,827	18,758	18,849	18,758
Additional Paid-in Capital
Balance	$ 350,658	$ 346,795	$ 330,763	$ 346,795	$ 326,208
Equity compensation	2,518		3,714	6,344	7,865
Exercise of stock options			25	37	429
Net payments for stock issuances and buybacks	1,024		843	1,024	843
Balance	354,200	350,658	335,345	354,200	335,345
Retained Earnings
Balance	552,303	544,840	499,126	544,840	486,442
Net income	13,656		14,611	24,268	29,929
Cumulative-effect adjustment for adoption of accounting principle				(513)
Dividends declared	(2,637)		(2,642)	(5,273)	(5,276)
Balance	563,322	552,303	511,095	563,322	511,095
Treasury Stock
Balance	$ (188,961)	$ (164,963)	$ (155,073)	$ (164,963)	$ (139,704)
Balance (in shares)	4,289	3,978	3,846	3,978	3,629
Net payments for stock issuances and buybacks	$ (50)		$ (9,632)	$ (24,048)	$ (25,001)
Net payments for stock issuances and buybacks (in shares)			129	311	346
Balance	$ (189,011)	$ (188,961)	$ (164,705)	$ (189,011)	$ (164,705)
Balance (in shares)	4,289	4,289	3,975	4,289	3,975
Accumulated Other Comprehensive Loss
Balance	$ (23,267)	$ (12,144)	$ (12,268)	$ (12,144)	$ (12,551)
Other comprehensive income (loss)	(164)		(2,853)	(11,287)	(2,570)
Balance	$ (23,431)	$ (23,267)	$ (15,121)	$ (23,431)	$ (15,121)