Property, Plant and Equipment (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Property, plant and equipment
Land	$ 1,764	$ 1,764
Building improvements	882,305	855,318
Capitalized leases for machinery, equipment and buildings	28,680	16,133
Property, plant and equipment, gross	912,749	873,215
Accumulated depreciation and amortization	(449,034)	(395,520)
Property Plant and Equipment Net before Construction in Progress	463,715	477,695
Construction in Progress	10,535	8,578
Property, plant and equipment, net	$ 474,250	$ 486,273