Schedule II (Details) (Allowance for doubtful accounts, USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2009
Allowance for doubtful accounts
Activity in Provision for Doubtful Accounts
Balance at the Beginning of the Period	$ 0		$ 0	$ 0
Charged to Revenue, Cost or Expense	213	12	255
Deduction	(213)	(12)	(255)
Balance at the End of the Period	$ 0	$ 0		$ 0