Income Taxes Asset Liability Net (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Deferred Tax Assets:
Federal net operating and credit loss carryforwards	$ 65,168	$ 30,395
Deferred revenue	137,688	128,733
Bad debt reserves	7,119	5,144
Employee benefits	43,684	43,249
Investment in affiliates	0	1,538
Accrued expenses and loss reserves	29,384	18,738
Other	2,519	2,615
Less: Valuation allowance	(29,389)	(19,058)
Total Deferred Tax Assets	256,173	211,354
Deferred Tax Liabilities:
Depreciable and amortizable assets	186,260	159,178
Investment in affiliates	10,407	0
Marketable equity securities	0	15,050
Total Deferred Tax Liabilities	196,667	174,228
Net deferred tax assets/(liabilities)	$ 59,506	$ 37,126