Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Summary of carrying amount and estimated fair values of financial instruments
Short-term borrowings, net	$ 31,625	$ 45,149
Long-term debt, net	158,943	178,043
Carrying Amount [Member]
Summary of carrying amount and estimated fair values of financial instruments
Short-term borrowings, net	31,625	45,149
Long-term debt, net	158,943	178,043
Fair Value [Member]
Summary of carrying amount and estimated fair values of financial instruments
Short-term borrowings	31,239	44,063
Long-term debt	$ 156,560	$ 166,600