Short-Term and Long-Term Debt Long-Term Debt (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Jul. 22, 2010
Revolving credit facility
Prime rate borrowings	$ 9,200	$ 0
LIBOR borrowings	15,000	20,000
Revolving credit facility, amount outstanding	24,200	20,000
Senior unsecured notes	30,000	30,000	30,000
Term loans	7,579	6,973
Long-term debt	61,779	56,973
Less current portion	6,992	5,837
Long-term debt, excluding current maturities	$ 54,787	$ 51,136