Debt Convertible Senior Notes Textual -Additional Information (Detail) $ / shares in Units, $ in Thousands	3 Months Ended			12 Months Ended
	Mar. 31, 2016 USD ($) d $ / shares	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 08, 2014 USD ($)
Debt Instrument [Line Items]
Gains (Losses) on Extinguishment of Debt	$ 421
Interest Expense, Debt	2,700
Amortization of debt discount (premium)	1,300
Interest Expense, Debt, Excluding Amortization	1,400
Repayments of Convertible Debt	4,459	$ 0
Convertible Debt [Member] | Senior 3 Point 25 Percent Convertible Notes Due 2020 [Member]
Debt Instrument [Line Items]
Gains (Losses) on Extinguishment of Debt	$ 421
Convertible Senior Notes, face amount			$ 172,500		$ 172,500
Senior Credit Facility, applicable margin	3.25%
Debt issuance cost			5,100
Deferred financing costs			4,200		$ 4,200
Remaining amortization period of discount on the liability component	4 years 9 months			5 years	6 years
Adjustments to additional paid in capital	$ 900
Convertible Senior Notes, conversion ratio	31.1891
Convertible Senior Notes, conversion price | $ / shares	$ 32.06
Convertible Senior Notes, threshold trading days | d	20
Convertible Senior Notes, threshold consecutive trading days	30 days
Convertible Senior Notes, threshold percentage of stock price trigger	130.00%
Convertible Senior Notes, threshold consecutive business days	5 days
Convertible Senior Notes, threshold consecutive trading days, following consecutive business days	5 days
Convertible Senior Notes, threshold percentage of stock price trigger, following consecutive business days	98.00%
Convertible Senior Notes, observation period	25 days
Interest Expense, Debt	$ 2,800
Amortization of debt discount (premium)	1,400
Interest Expense, Debt, Excluding Amortization	$ 1,400
Debt Conversion, Converted Instrument, Rate	100.00%
Debt Instrument, Interest Rate, Effective Percentage	6.90%
Convertible Senior Notes, fair value disclosures			$ 141,900		$ 141,900
Carrying value of equity component, net of issuance costs	$ 29,211			$ 29,758		$ 30,700
Repurchase of Convertible Debt	5,200
Repayments of Convertible Debt	4,500
Other Current Assets [Member]
Debt Instrument [Line Items]
Deferred financing costs	300			300
Other Current Assets [Member] | Convertible Debt [Member] | Senior 3 Point 25 Percent Convertible Notes Due 2020 [Member]
Debt Instrument [Line Items]
Deferred financing costs	(3,236)			3,500
Other non-current assets [Member]
Debt Instrument [Line Items]
Deferred financing costs	$ 100			$ 200