Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018
Current assets:
Cash and cash equivalents	$ 244,648	$ 286,846
Accounts receivable, net (1)	160,731	146,561
Inventories, net	205,956	204,386
Prepaid expenses and other current assets	39,383	41,160
Total current assets (1)	650,718	678,953
Noncurrent Assets:
Property, plant and equipment, net of accumulated depreciation of $856,765 and $866,614 as of June 30, 2018 and March 31, 2018, respectively	397,123	405,316
Goodwill	40,294	40,294
Intangible assets, net	57,297	59,907
Equity Method Investments	11,212	12,016
Deferred income taxes	11,441	13,837
Other assets (1)	10,977	12,600
Total assets (1)	1,179,062	1,222,923
Current liabilities:
Current portion of long-term debt	20,412	20,540
Accounts payable	143,125	139,989
Accrued expenses (1)	98,315	125,119
Income taxes payable	5,301	2,010
Total current liabilities (1)	267,153	287,658
Liabilities, Noncurrent [Abstract]
Long-term debt	299,811	304,083
Other non-current obligations (1)	129,034	152,249
Deferred income taxes (1)	14,090	15,058
Liabilities	710,088	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 57,347 and 56,641 shares at June 30, 2018 and March 31, 2018, respectively	573	566
Additional paid-in capital	461,261	462,737
Retained earnings (deficit) (1)	38,590	3,370
Accumulated other comprehensive income (loss) (1)	(31,450)	(2,798)
Total stockholders’ equity (1)	468,974	463,875
Total liabilities and stockholders’ equity (1)	$ 1,179,062	$ 1,222,923