Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net (loss) income	$ (23,138)	$ 12,896
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation	101,659	100,541
Amortization of intangible assets	23,150	21,279
Deferred income taxes	(21,313)	3,430
Equity in income of unconsolidated affiliate, net	(228)
Stock-based compensation expense	31,490	25,418
Loss on disposition of fixed assets	17,853	17,812
Loss on extinguishment of debt	10,217
Other non-cash adjustments	4,481	4,895
Increase (decrease) in cash resulting from changes in operating assets and liabilities
Accounts receivable	7,657	6,494
Inventories	(12,455)	(2,074)
Other assets	(18,277)	(5,907)
Accounts payable	(7,744)	(8,876)
Accrued liabilities	5,984	13,404
Other liabilities	66,490	2,315
Net cash provided by operating activities	185,826	191,627
Cash flows from investing activities:
Purchase of property, equipment and satellites	(206,627)	(260,033)
Cash paid for patents, licenses and other assets	(36,969)	(38,430)
Other investing activities		(649)
Net cash used in investing activities	(243,596)	(299,112)
Cash flows from financing activities:
Payment of debt issuance costs	(8,735)	(6,583)
Proceeds from issuance of common stock under equity plans	14,871	14,487
Purchase of common stock in treasury (immediately retired) related to tax withholdings for stock-based compensation	(2,483)	(2,504)
Other financing activities	(757)	(761)
Net cash provided by financing activities	169,797	116,875
Effect of exchange rate changes on cash	583	(203)
Net increase in cash and cash equivalents	112,610	9,187
Cash and cash equivalents at beginning of period	130,098	42,088
Cash and cash equivalents at end of period	242,708	51,275
Non-cash investing and financing activities:
Issuance of common stock in satisfaction of certain accrued employee compensation liabilities	16,409	13,080
Capital expenditures not paid for	13,003	19,923
Revolving Credit Facility [Member]
Cash flows from financing activities:
Proceeds from credit facility borrowings		90,000
Payments of revolving credit facility borrowings		(45,000)
Ex-Im Credit Facility [Member]
Cash flows from financing activities:
Proceeds from credit facility borrowings	52,503	67,236
Non-cash investing and financing activities:
Exposure fees on Ex-Im credit facility financed through Ex-Im credit facility	5,764	$ 7,382
2025 Notes [Member]
Cash flows from financing activities:
Proceeds from issuance of 2025 Notes	700,000
2020 Notes [Member]
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Loss on extinguishment of debt	10,217
Cash flows from financing activities:
Repayment of 2020 Notes	(575,000)
Payment of debt extinguishment costs	$ (10,602)