Share Based Awards (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2012 Y	Mar. 31, 2012 Y
Summary of Stock Option Activity
Number of Shares Outstanding Beginning Balance	988,337
Weighted Average Exercise Price per Share Outstanding Beginning Balance	$ 32.09
Weighted Average Remaining Contractual Life Outstanding Beginning Balance (in years)	6.2	5.4
Aggregate Intrinsic Value Outstanding Beginning Balance
Number of Share Granted	491,500
Weighted Average Exercise Price per Share Granted	$ 29.24
Weighted Average Remaining Contractual Life Granted (in years)	7.9
Number of Shares Exercised	(45,366)
Weighted Average Exercise Price per Share Exercised	$ 16.83
Weighted Average Remaining Contractual Life Exercised (in years)	0.8
Aggregate Intrinsic Value, Exercised	485
Number of Shares Forfeited/Canceled	(2,000)
Weighted Average Exercise Price per Share Forfeited/Canceled	$ 29.75
Weighted Average Remaining Contractual Life Forfeited/Canceled (in years)	5.4
Number of Shares Outstanding Ending Balance	1,432,471
Weighted Average Exercise Price per Share Outstanding Ending Balance	$ 31.60
Weighted Average Remaining Contractual Life Outstanding Ending Balance (in years)	6.2	5.4
Aggregate Intrinsic Value Outstanding Ending Balance	1,277
Number of Shares Vested and expected to vest	1,388,433
Weighted Average Exercise Price per Share Vested and expected to vest	$ 31.60
Weighted Average Remaining Contractual Life Vested and expected to vest (in years)	6.2
Aggregate Intrinsic Value Vested and expected to vest	1,246
Number of Shares Exercisable	299,186
Weighted Average Exercise Price per Share Exercisable	$ 29.02
Weighted Average Remaining Contractual Life Exercisable (in years)	4.4
Aggregate Intrinsic Value Exercisable	$ 847