Fair Value Measurements (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value Measurements Abstract
Non-financial assets and liabilities measured at fair value on a nonrecurring basis	$ 0	$ 0
Fair value level 1 to level 2 transfers, description	(1) Transferred from Level 1, as of December 31, 2011, to Level 2, as of December 31, 2012, within the hierarchy due to the absence of unadjusted, quoted prices in active markets.