Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Current assets:
Cash and cash equivalents	$ 208,448
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	209,861	$ 207,918
Accounts receivable, net	142,007	154,059
Inventories, net	263,123	241,129
Prepaid expenses and other current assets	42,044	38,947
Total current assets	655,622	642,053
Noncurrent Assets:
Property, plant and equipment, net of accumulated depreciation of $911,634 and $880,451 as of December 31, 2019 and March 31, 2019, respectively	548,594	495,280
Goodwill	40,294	40,294
Intangible assets, net	55,117	53,749
Equity method investments	16,641	12,925
Equity method investments	47,871	57,024
Other assets	48,193	16,770
Total assets	1,412,332	1,318,095
Current liabilities:
Current portion of long-term debt	29,032	28,430
Accounts payable	111,465	153,287
Accrued expenses	130,991	93,761
Income taxes payable	3,981	2,995
Total current liabilities	275,469	278,473
Liabilities, Noncurrent [Abstract]
Long-term debt	282,746	266,041
Other non-current obligations	153,025	125,360
Deferred Tax Liabilities, Net, Noncurrent	13,779	8,806
Liabilities	725,019	678,680
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 58,267 and 57,822 shares at December 31, 2019 and March 31, 2019, respectively	583	578
Additional paid-in capital	471,641	465,366
Retained earnings (deficit)	240,074	204,195
Accumulated other comprehensive income (loss)	(24,985)	(30,724)
Total stockholders’ equity	687,313	639,415
Total liabilities and stockholders’ equity	$ 1,412,332	$ 1,318,095