Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 12,896	$ 7,439
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	100,541	94,996
Amortization of intangible assets	21,279	23,433
Deferred income taxes	3,430	3,814
Stock-based compensation expense	25,418	22,283
Loss on disposition of fixed assets	17,812	17,862
Other non-cash adjustments	4,895	3,697
Increase (decrease) in cash resulting from changes in operating assets and liabilities, net of effects of acquisition:
Accounts receivable	6,494	(41,073)
Inventories	(2,074)	(4,472)
Other assets	(5,907)	(4,367)
Accounts payable	(8,876)	(3,703)
Accrued liabilities	13,404	(10,210)
Other liabilities	2,315	(2,201)
Net cash provided by operating activities	191,627	107,498
Cash flows from investing activities:
Purchase of property, equipment and satellites	(260,033)	(137,517)
Cash paid for patents, licenses and other assets	(38,430)	(32,483)
Payments related to acquisition of business, net of cash acquired		(3,613)
Other investing activities	(649)
Net cash used in investing activities	(299,112)	(173,613)
Cash flows from financing activities:
Payment of debt issuance costs	(6,583)	(803)
Proceeds from issuance of common stock under equity plans	14,487	11,422
Purchase of common stock in treasury (immediately retired) related to tax withholdings for stock-based compensation	(2,504)	(1,339)
Other financing activities	(761)	(886)
Net cash provided by financing activities	116,875	60,244
Effect of exchange rate changes on cash	(203)	14
Net increase (decrease) in cash and cash equivalents	9,187	(5,857)
Cash and cash equivalents at beginning of period	42,088	52,263
Cash and cash equivalents at end of period	51,275	46,406
Non-cash investing and financing activities:
Issuance of common stock in satisfaction of certain accrued employee compensation liabilities	13,080	11,609
Capital expenditures not paid for	19,923	22,957
Revolving Credit Facility [Member]
Cash flows from financing activities:
Proceeds from credit facility borrowings	90,000	100,000
Payments of revolving credit facility borrowings	(45,000)	(145,000)
Ex-Im Credit Facility [Member]
Cash flows from financing activities:
Proceeds from credit facility borrowings	67,236	96,850
Non-cash investing and financing activities:
Exposure fees on Ex-Im credit facility expected to be financed through Ex-Im credit facility	$ 7,382	$ 8,443