Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, plant and equipment
Land	$ 8,287	$ 1,752
Building improvements	654,585	647,181
Capitalized leases for machinery, equipment and buildings	30,648	28,680
Property, plant and equipment, gross	693,520	677,613
Accumulated depreciation and amortization	(514,509)	(464,852)
Property Plant and Equipment Net before Construction in Progress	179,011	212,761
Construction in Progress	16,988	15,150
Property, plant and equipment, net	195,999	227,911
Rent expense, operating leases	$ 14,300	$ 11,200	$ 16,700