Segment Information - Segment Revenues and Operating Profits (Losses) (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Product revenues	$ 160,676	$ 168,348
Income (loss) from operations	7,778	9,414
Operating Segments [Member]
Segment Reporting Information [Line Items]
Income (loss) from operations	10,291	14,224
Operating Segments [Member] | Satellite Services [Member]
Segment Reporting Information [Line Items]
Product revenues	6,685	6,276
Income (loss) from operations	30,867	17,041
Operating Segments [Member] | Implied License [Member] | Satellite Services [Member]
Segment Reporting Information [Line Items]
Product revenues	6,600	6,200
Income (loss) from operations	$ 6,600	$ 6,200