Stock-Based Compensation (Details)	3 Months Ended
	Jun. 30, 2012
2013 $2.36 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.00%
Risk-free interest rate	1.20%
Expected term of options (in years)	7 years
2012 $2.75 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.60%
Risk-free interest rate	1.50%
Expected term of options (in years)	7 years
2012 $2.58 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.80%
Risk-free interest rate	1.60%
Expected term of options (in years)	7 years
2012 $2.72 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.80%
Risk-free interest rate	1.60%
Expected term of options (in years)	7 years
2012 $2.81 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.40%
Risk-free interest rate	1.90%
Expected term of options (in years)	7 years
2012 $2.13 value per option [Member]
Assumptions to estimate the fair value of option grants
Dividend yield	0.00%
Volatility	25.30%
Risk-free interest rate	1.90%
Expected term of options (in years)	7 years