Income Taxes - Deferred Portion of Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Amortization of franchise rights	$ 500	$ 514	$ 514
Amortization of other intangibles	1,221	1,590	1,241
Accrued expenses, deducted for tax when paid	(6,889)	(17,664)	(14,221)
Capitalized costs for books, deducted for tax	5,901	5,315	8,809
Depreciation	(2,405)	(5,932)	(4,147)
Federal impact of unrecognized tax benefits	75	1,058	44
Foreign tax credit carryforwards	0	3,636	(186)
Other, net	(271)	2,904	4,303
Deferred Portion Of Tax Expense Benefit, Total	$ (1,868)	$ (8,579)	$ (3,643)