Fair Value Measurements (Details) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Mar. 31, 2013
ASSETS
Cash and cash equivalents	$ 72,816	[1]	$ 105,999	[1]
Restricted cash	3,498		5,488
Marketable securities	11,489	[2]	12,012	[2]
Total	87,803		123,499
LIABILITIES
Contingent consideration related to acquisitions	16,559		5,336
Total	16,559		5,336
Quoted Prices in Active Markets for Identical Assets (Level 1)
ASSETS
Cash and cash equivalents	72,816	[1]	105,999	[1]
Restricted cash	3,498		5,488
Marketable securities	11,489	[2]	12,012	[2]
Total	87,803		123,499
LIABILITIES
Contingent consideration related to acquisitions	0		0
Total	0		0
Significant Other Observable Inputs (Level 2)
ASSETS
Cash and cash equivalents	0	[1]	0	[1]
Restricted cash	0		0
Marketable securities	0	[2]	0	[2]
Total	0		0
LIABILITIES
Contingent consideration related to acquisitions	0		0
Total	0		0
Unobservable Inputs (Level 3)
ASSETS
Cash and cash equivalents	0	[1]	0	[1]
Restricted cash	0		0
Marketable securities	0	[2]	0	[2]
Total	0		0
LIABILITIES
Contingent consideration related to acquisitions	16,559		5,336
Total	$ 16,559		$ 5,336

[1] Cash equivalents consists of money market funds.

[2] Marketable securities consist of fixed-income securities.