CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - 6 months ended Jun. 30, 2018 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]
Balance at Dec. 31, 2017	$ 66,321	$ 555	$ 25,337	$ (256,363)	$ 296,792
Purchase of treasury stock, at cost	(16,227)	0	0	(16,227)	0
Issuance of long-term incentive awards and dividend equivalents	0	0	(5,764)	6,619	(855)
Stock-based compensation expense	8,887	0	7,005	1,882	0
Other	1,110	0	785	325	0
Dividends paid	(16,786)	0	0	0	(16,786)
Unrealized gain on marketable securities, net of tax	4	0	0	0	4
Net income	74,551	0	0	0	74,551
Balance at Jun. 30, 2018	$ 117,860	$ 555	$ 27,363	$ (263,764)	$ 353,706
Balance (shares) at Dec. 31, 2017		55,489
Balance (shares) at Jun. 30, 2018		55,489