Long-Term Debt Long-Term Debt - Interest Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Interest costs expensed	$ 17,914	$ 18,228	$ 22,617
Interest costs capitalized	72	300	32
Total interest expense and amounts capitalized	17,986	18,528	$ 22,649
Interest expense, building financing arrangement	$ 2,666	$ 810