Commitments and Contingencies (Details) (USD $) In Millions, except Share data, unless otherwise specified		1 Months Ended			1 Months Ended
	Mar. 31, 2011 ATME arbitration [Member]	Mar. 31, 2006 Class action litigation [Member]	Mar. 31, 2007 Opt-out claims: 380544 Canada action [Member]	Feb. 15, 2007 Opt-out claims: 380544 Canada action [Member]	Apr. 30, 2004 Customer claim [Member]
Loss Contingencies [Line Items]
Possible termination fee on alleged breached agreement, minimum	$ 60
Possible termination fee on alleged breached agreement, maximum	77
Common stock held by class members who opted out of settlement (in shares)		1,457,969
Maximum percentage of total shares purchased during class action period by shareholders who opted out of the settlement (in hundredths)		1.00%
Common stock owned by stockholders who filed opt-out claims (in shares)		1,100,000		566,665
Number of pending opt-out claims				1
Amount of damages sought			$ 4.0		$ 5.0