Commitments, Contingencies and Guarantees - Summary of Contractual Obligations (Parenthetical) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Jul. 29, 2011	Dec. 09, 2014
Loss Contingencies [Line Items]
Sub-lease payments receivables	$ 9,000,000
Total contractual obligations more than 5 years	405,737,000
Interest on Notes Payable [Member]
Loss Contingencies [Line Items]
Total contractual obligations more than 5 years	205,258,000	[1]
8.75% Convertible Note [Member]
Loss Contingencies [Line Items]
Convertible notes rate	8.75%
Principal amount of notes	150,000,000
Principal amount of notes	150,000,000
4.50% Convertible Notes [Member]
Loss Contingencies [Line Items]
Convertible notes rate	4.50%		4.50%	4.50%
Principal amount of notes	160,000,000		160,000,000	160,000,000
Principal amount of notes	160,000,000		160,000,000	160,000,000
Carrying value of note	152,500,000
8.125% Convertible Notes [Member]
Loss Contingencies [Line Items]
Convertible notes rate	8.125%
Principal amount of notes	112,500,000
Principal amount of notes	112,500,000
Carrying value of note	109,000,000
8.125% Convertible Notes [Member] | Interest on Notes Payable [Member]
Loss Contingencies [Line Items]
Total contractual obligations more than 5 years	205,300,000
5.375% Senior Notes [Member]
Loss Contingencies [Line Items]
Convertible notes rate	5.375%		5.375%
Principal amount of notes	300,000,000				300,000,000
Principal amount of notes	300,000,000				300,000,000
Carrying value of note	$ 295,200,000

[1] The $205.3 million of interest on notes payable that are due in more than five years represents interest on the 8.125% Senior Notes. The 8.125% Senior Notes may be redeemed for cash, in whole or in part, on or after June 26, 2017, at the Company's option, which may impact the actual interest paid.