Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2018	Mar. 31, 2018
Current assets:
Cash and cash equivalents	$ 263,047	$ 286,846
Accounts receivable, net (1)	157,013	146,561
Inventories, net	213,268	204,386
Prepaid expenses and other current assets	36,320	41,160
Total current assets (1)	669,648	678,953
Noncurrent Assets:
Property, plant and equipment, net of accumulated depreciation of $857,866 and $866,614 as of September 30, 2018 and March 31, 2018, respectively	408,076	405,316
Goodwill	40,294	40,294
Intangible assets, net	55,457	59,907
Equity Method Investments	12,215	12,016
Deferred Tax Assets, Net, Noncurrent	12,124	13,837
Other assets (1)	11,783	12,600
Total assets (1)	1,209,597	1,222,923
Current liabilities:
Current portion of long-term debt	20,553	20,540
Accounts payable	138,253	139,989
Accrued expenses (1)	96,666	125,119
Income taxes payable	2,584	2,010
Total current liabilities (1)	258,056	287,658
Liabilities, Noncurrent [Abstract]
Long-term debt	296,084	304,083
Other non-current obligations (1)	128,427	152,249
Deferred Tax Liabilities, Net, Noncurrent	14,459	15,058
Liabilities	697,026	759,048
Stockholders’ equity:
Preferred stock, par value $0.01, authorized 10,000 shares, none issued	0	0
Common stock, par value $0.01, authorized 175,000 shares, issued 57,436 and 56,641 shares at September 30, 2018 and March 31, 2018, respectively	574	566
Additional paid-in capital	465,474	462,737
Retained earnings (deficit) (1)	75,731	3,370
Accumulated other comprehensive income (loss) (1)	(29,208)	(2,798)
Total stockholders’ equity (1)	512,571	463,875
Total liabilities and stockholders’ equity (1)	$ 1,209,597	$ 1,222,923