Consolidated Statements Of Shareholders' Equity - 3 months ended Mar. 31, 2017 - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]
BALANCE at Dec. 31, 2016	$ 23,458	$ 651	$ 1,665,891	$ (1,643,084)
BALANCE, shares at Dec. 31, 2016		65,132,499
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	6,448		6,448
Issuance of common stock upon grants of restricted stock awards, net of forfeitures, and vestings of restricted stock units and performance shares	0	$ 7	(7)
Issuance of common stock upon grants of restricted stock awards, net of forfeitures, and vestings of restricted stock units and performance shares, shares		663,843
Net Income (loss)	40,021			40,021
BALANCE at Mar. 31, 2017	$ 69,927	$ 658	$ 1,672,332	$ (1,603,063)
BALANCE, shares at Mar. 31, 2017		65,796,342