Termination Charges (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Termination charges	$ 2,900,000	$ 6,600,000	$ 3,300,000
Termination benefits expected to be paid within next 12 months	3,099,000	4,522,000
Salary and Benefits Continuation [Member]
Termination charges		5,800,000
Termination benefits remaining to be paid	2,200,000
Salary and Benefits Continuation [Member] | Prior Period [Member]
Termination benefits remaining to be paid	0
Special Termination Benefits [Member]
Termination charges		800,000
Salary and Benefits Continuation AND Special Termination Benefits [Member]
Termination benefits remitted by company	5,200,000
Termination benefits paid for charges recorded in prior periods	4,600,000
Termination benefits included in liabilities	3,100,000
Prior period termination benefits unpaid	200,000
Termination benefits expected to be paid within next 12 months	3,100,000
Salary and Benefits Continuation AND Special Termination Benefits [Member] | Prior Period [Member]
Termination benefits remaining to be paid	$ 700,000