Income Tax (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Income Taxes (Textual) ) [Abstract]
Provision for income taxes	$ 8,811	$ 11,002	$ 16,643	$ 20,882
Effective tax rate (as a percentage)	36.00%	34.90%	34.80%	34.60%
Liability for unrecognized tax benefits	563		563
Unrecognized tax benefits that would impact effective tax rate	563		563
Decrease in liability for unrecognized tax benefits due to the expiration of the statute of limitations of prior year tax positions of acquired companies			$ 79
Period within which the company does not anticipate total unrecognized tax benefits to change			within the next twelve months