Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Investments
Fair value of equity security investments	$ 3,200,000	$ 4,300,000
Goodwill
Long-term growth rate used to calculate terminal values for each reporting unit (as a percent)	3.00%
Inventory
Raw materials	128,606,000	148,822,000
Work-in-progress	26,762,000	45,733,000
Finished goods	54,425,000	56,578,000
Total inventory	$ 209,793,000	$ 251,133,000	$ 262,587,000