Condensed Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Retained (Loss) Earnings	Treasury Stock
Beginning Balances at Dec. 31, 2017	$ (1,154,636)	$ 2,116,018	$ (3,270,605)	$ (49)
Beginning Balances, Shares at Dec. 31, 2017		196,347
Employee stock plan grants, Shares		1,226
Net share settlements	(2,061)		(2,061)
Net share settlements, Shares		(519)
Fair value of employee stock plan grants	10,709	$ 10,709
Initial adoption | ASC 606	1,761		1,761
Net income	47,493		47,493
Ending Balances at Mar. 31, 2018	(1,096,734)	$ 2,126,727	(3,223,412)	(49)
Ending Balances, Shares at Mar. 31, 2018		197,054
Beginning Balances at Dec. 31, 2018	(1,048,622)	$ 2,137,443	(3,186,016)	(49)
Beginning Balances, Shares at Dec. 31, 2018		197,383
Fair value of employee stock plan grants	1,127	$ 1,127
Initial adoption | ASC 842	92,818		92,818
Net income	40,674		40,674
Ending Balances at Mar. 31, 2019	$ (914,003)	$ 2,138,570	$ (3,052,524)	$ (49)
Ending Balances, Shares at Mar. 31, 2019		197,383