Condensed Consolidated Statement Of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Beginning balance at Dec. 31, 2019	$ 800,672	$ 281	$ 212,485	$ 644,945	$ 1,123	$ (58,162)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	28,214			28,214
Issuance of shares of common stock pursuant to stock-based awards, net of shares tendered for payment of taxes	(4,517)	1	(4,518)
Stock-based compensation expense	3,295		3,295
Other comprehensive income (loss)	(3,540)				(3,540)
Cash dividends	(16,321)			(16,321)
Dividend equivalents on stock-based awards	0		297	(297)
Ending balance at Mar. 31, 2020	807,803	282	211,559	656,541	(2,417)	(58,162)
Beginning balance at Dec. 31, 2020	908,326	282	227,407	731,710	7,089	(58,162)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	74,120			74,120
Issuance of shares of common stock pursuant to stock-based awards, net of shares tendered for payment of taxes	(7,767)	1	(7,768)
Stock-based compensation expense	7,436		7,436
Other comprehensive income (loss)	(3,589)				(3,589)
Cash dividends	(18,939)			(18,939)
Dividend equivalents on stock-based awards	0		325	(325)
Ending balance at Mar. 31, 2021	$ 959,587	$ 283	$ 227,400	$ 786,566	$ 3,500	$ (58,162)