Fair Value Measurements (Details) (USD $) In Thousands	Jun. 30, 2011	Mar. 31, 2011
Fair Value Assets Measured on Recurring Basis
Cash and cash equivalents	$ 124,054	$ 116,617
Restricted cash	4,487	3,787
Marketable securities	1,110	1,120
Total	129,651	121,524
Fair Value Liabilities Measured on Recurring Basis
Contingent consideration related to acquistions	1,616	13,658
Total	1,616	13,658
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Assets Measured on Recurring Basis
Cash and cash equivalents	124,054	116,617
Restricted cash	4,487	3,787
Marketable securities	1,110	1,120
Total	129,651	121,524
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value Liabilities Measured on Recurring Basis
Contingent consideration related to acquistions	0	0
Total	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Assets Measured on Recurring Basis
Cash and cash equivalents	0	0
Restricted cash	0	0
Marketable securities	0	0
Total	0	0
Significant Other Observable Inputs (Level 2) [Member]
Fair Value Liabilities Measured on Recurring Basis
Contingent consideration related to acquistions	0	12,743
Total	0	12,743
Unobservable Inputs (Level 3) [Member]
Fair Value Assets Measured on Recurring Basis
Cash and cash equivalents	0	0
Restricted cash	0	0
Marketable securities	0	0
Total	0	0
Unobservable Inputs (Level 3) [Member]
Fair Value Liabilities Measured on Recurring Basis
Contingent consideration related to acquistions	1,616	915
Total	$ 1,616	$ 915