Income Taxes (Asset/Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Net losses and credit carryforwards	$ 92,537	$ 98,633
Deferred revenue	132,359	137,090
Bad debt reserves	1,042	2,962
Employee benefits	46,586	47,414
Accrued expenses and loss reserves	32,796	29,791
Other	0	(989)
Less: valuation allowance	(19,171)	(21,912)
Total deferred tax assets	286,149	292,989
Deferred tax liabilities:
Depreciable and amortizable assets	279,435	247,458
Investment in affiliates	11,199	19,169
Other	4,658	0
Deferred tax liabilities	295,292	266,627
Net deferred tax liabilities	$ (9,143)
Net deferred tax assets		$ 26,362