Commitments and Contingencies (Details 2) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Capital Expenditure Commitments
Capital expenditures under current construction program for 2015	$ 31,400
Contractual commitment to spend on capital expenditures	2,000
Purchase obligations
Obligations to purchase various goods and services	87,100
Obligations to be incurred in 2015	62,700
Other Lease Agreements
Operating Leased Assets [Line Items]
Total rental expense	37,900	$ 33,300	$ 36,400
Future minimum lease commitments relating to the base lease rent portion of noncancelable operating leases
2016	4,223
2017	3,205
2018	2,668
2019	1,632
2020	1,066
Thereafter	14,831
Total	$ 27,625