Long-Term Debt Long-Term Debt - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Interest costs expensed	$ 13,904	$ 17,914	$ 18,228
Interest costs capitalized	28	72	300
Total interest expense and amounts capitalized	$ 13,932	17,986	18,528
Interest expense, building financing arrangement		$ 2,666	$ 810