Segment Information- Net Sales and Operating Income by Operating Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
Net sales	$ 470,320	$ 482,203
Segment operating income (loss)	6,970	22,712
Other income (expense):
Restructuring charges, net	(12,995)	0
Share-based compensation	(6,749)	(6,938)
Amortization of intangibles	(732)	(2,782)
Interest income, net	264	258
Other expense, net	(1,121)	(198)
Income before income taxes	6,113	22,772
Operating Segments
Segment Reporting Information [Line Items]
Segment operating income (loss)	27,446	32,432
Peripherals
Other income (expense):
Restructuring charges, net	(11,500)
Peripherals | Operating Segments
Segment Reporting Information [Line Items]
Net sales	447,686	456,446
Segment operating income (loss)	31,847	33,567
Video conferencing
Other income (expense):
Restructuring charges, net	(1,500)
Video conferencing | Operating Segments
Segment Reporting Information [Line Items]
Net sales	22,634	25,757
Segment operating income (loss)	$ (4,401)	$ (1,135)