CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury Stock	Total
Balance at Jun. 30, 2017	$ 37	$ 292,780	$ 277,774	$ (222)	$ (9,247)	$ 561,122
Balance (in shares) at Jun. 30, 2017	37,528
Increase (Decrease) in Shareholders' Equity
Shares issued in connection with share-based compensation plans	$ 1	805				806
Shares issued in connection with share-based compensation plans (in shares)	233
Share-based compensation		4,752				4,752
Purchase of treasury stock					(1,038)	(1,038)
Other comprehensive income (loss), net of tax				(125)		(125)
Net income (loss)			27,279			27,279
Balance at Dec. 31, 2017	$ 38	298,337	305,053	(347)	(10,285)	592,796
Balance (in shares) at Dec. 31, 2017	37,761
Balance at Sep. 30, 2017	$ 38	295,282	291,031	(221)	(9,859)	576,271
Balance (in shares) at Sep. 30, 2017	37,672
Increase (Decrease) in Shareholders' Equity
Shares issued in connection with share-based compensation plans		492				492
Shares issued in connection with share-based compensation plans (in shares)	89
Share-based compensation		2,563				2,563
Purchase of treasury stock					(426)	(426)
Other comprehensive income (loss), net of tax				(126)		(126)
Net income (loss)			14,022			14,022
Balance at Dec. 31, 2017	$ 38	298,337	305,053	(347)	(10,285)	592,796
Balance (in shares) at Dec. 31, 2017	37,761
Balance at Jun. 30, 2018	$ 38	306,817	306,464	(515)	(13,889)	598,915
Balance (in shares) at Jun. 30, 2018	38,257
Increase (Decrease) in Shareholders' Equity
Other comprehensive income (loss), net of tax						13
Net income (loss)						(275,166)
Balance at Dec. 31, 2018	$ 39	312,322	29,016	(502)	(14,364)	326,511
Balance (in shares) at Dec. 31, 2018	38,767
Increase (Decrease) in Shareholders' Equity
ASC 606 adjustment | ASU 2014-09			(2,282)			(2,282)
Shares issued in connection with share-based compensation plans	$ 1	520				521
Shares issued in connection with share-based compensation plans (in shares)	510
Share-based compensation		4,985				4,985
Purchase of treasury stock					(475)	(475)
Other comprehensive income (loss), net of tax				13		13
Net income (loss)			(275,166)			(275,166)
Balance at Dec. 31, 2018	$ 39	312,322	29,016	(502)	(14,364)	326,511
Balance (in shares) at Dec. 31, 2018	38,767
Balance at Sep. 30, 2018	$ 39	310,135	16,654	(509)	(14,295)	312,024
Balance (in shares) at Sep. 30, 2018	38,665
Increase (Decrease) in Shareholders' Equity
Shares issued in connection with share-based compensation plans		237				237
Shares issued in connection with share-based compensation plans (in shares)	102
Share-based compensation		1,950				1,950
Purchase of treasury stock					(69)	(69)
Other comprehensive income (loss), net of tax				7		7
Net income (loss)			12,362			12,362
Balance at Dec. 31, 2018	$ 39	$ 312,322	$ 29,016	$ (502)	$ (14,364)	$ 326,511
Balance (in shares) at Dec. 31, 2018	38,767