Subsequent Events (Details) (Common stock, Subsequent event, USD $) In Millions, unless otherwise specified	0 Months Ended
Jan. 11, 2013
Common stock \| Subsequent event
Subsequent events:
Stock repurchase plan, authorized amount	$ 15

The amount authorized by an entity's Board of Directors under a stock repurchase plan.

No definition available.

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration