Short-term and Long-term Debt - Line of Credit (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Revolving line of credit
Line of Credit Facility [Line Items]
Line of credit amount	$ 30,000,000
Line of credit outstanding balance	0	0
Tangible net worth	324,880,000
Liquid Assets	64,467,000
Revolving line of credit | Minimum
Line of Credit Facility [Line Items]
Minimum tangible net worth required	225,000,000
Liquid assets	25,000,000
Revolving line of credit | Selected LIBOR rate
Line of Credit Facility [Line Items]
Interest rate on line of credit, variable rate	1.75%
Revolving line of credit | LIBOR for a fixed rate term
Line of Credit Facility [Line Items]
Interest rate on line of credit, variable rate	1.50%
Line of Credit
Line of Credit Facility [Line Items]
Line of credit amount	$ 94,467,000