Debt - Schedule of Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Line of Credit Facility [Line Items]
Debt	$ 432,744	$ 357,407
6% Tangible Equity Units [Member]
Line of Credit Facility [Line Items]
Debt	17,154	25,619
Term Loan Facility [Member] | Senior Secured Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt	0	200,000
Senior Notes [Member]
Line of Credit Facility [Line Items]
Debt	250,000	0
Convertible Debt [Member]
Line of Credit Facility [Line Items]
Debt	103,194	99,890
Secured Promissory Notes [Member]
Line of Credit Facility [Line Items]
Debt	15,400	15,400
Other Indebtedness [Member]
Line of Credit Facility [Line Items]
Debt	$ 46,996	$ 16,498