Bank Credit Agreements and Other Short-Term and Long-Term Debt (Bank Credit Agreement) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	$ 101,581
Lines of credit amount outstanding	7,629	8,000
Unsecured [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	81,581
Debt Instrument, Interest Rate Terms	Unsecured, interest at LIBOR plus margin, due quarterly
Lines of credit amount outstanding	5,629	0
Secured [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	10,000
Debt Instrument, Interest Rate Terms	Secured, interest at LIBOR plus margin, due monthly (Revolver)
Lines of credit amount outstanding	2,000	8,000
Secured Uncommitted [Member]
Line of Credit Facility [Line Items]
Lines of credit maximum borrowing capacity	10,000
Debt Instrument, Interest Rate Terms	Secured, uncommitted, interest at LIBOR plus margin, due monthly (Uncommitted Facility)
Lines of credit amount outstanding	$ 0	$ 0