Stockholders' Equity - Repurchase Program Activity (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012	Mar. 31, 2011
Summary of Repurchase Program Activity
Stock repurchase program, Authorized amount	$ 300,000
Total repurchases, Aggregate Price	653		20,852	40,063
Available for repurchase, Aggregate Price	15,872
Open market repurchases [Member]
Summary of Repurchase Program Activity
Total repurchases, Aggregate Price	173,611
Total repurchases, Repurchased Shares	17,284
Total repurchases, Average Price Per Share (USD per share)	$ 10.04
Structured stock repurchase agreements [Member]
Summary of Repurchase Program Activity
Total repurchases, Aggregate Price	110,517	[1]
Total repurchases, Repurchased Shares	9,989	[1]
Total repurchases, Average Price Per Share (USD per share)	$ 11.06	[1]
All Stock Repurchase Program [Member]
Summary of Repurchase Program Activity
Total repurchases, Aggregate Price	$ 284,128
Total repurchases, Repurchased Shares	27,273
Total repurchases, Average Price Per Share (USD per share)	$ 10.42

[1] The amounts above do not include gains recorded to additional paid-in-capital of $12.8 million from structured stock repurchase agreements which settled in cash. The average price per share for structured stock repurchase agreements adjusted for gains from settlements in cash would have been $9.78 per share and for total repurchases would have been $9.97 per share.