Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 793
Net income	(793)
Other comprehensive income	0
Purchases	0
Issuances	0
Sales	0
Settlements	0
Net transfers into / (out of) Level 3	0
Balance at end of period	$ 0