Unsolicited Takeover Attempt (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended	26 Months Ended
Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012
Unsolicited Takeover Attempt, Description [Abstract]
Costs (benefits) related to unsolicited takeover attempt	$ 0	$ (1,170)	$ 0	$ (6,700)	$ 0	$ (7,870)	$ 44,406	$ 60,000

Costs incurred in connection with an unsolicited tender offer (one where the Entity being sought has not requested the offer). These would include costs relating to evaluation and dissemination of information regarding an unsolicited tender offer. A tender offer is a broad solicitation by an Entity or a third party to purchase a substantial percentage of another entity's shares or units for a limited period of time. The offer is at a fixed price, usually at a premium over the current market price, and is contingent on shareholders' tendering a fixed number of their shares or units.

No definition available.

Name:	us-gaap_UnsolicitedTenderOfferCosts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration