Debt Convertible Senior Notes Textual -Additional Information (Detail)	3 Months Ended	6 Months Ended		12 Months Ended
	Jun. 30, 2017 USD ($) $ / shares	Jun. 30, 2017 USD ($) d $ / shares	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)	Dec. 08, 2014 USD ($)
Debt Instrument [Line Items]
Interest expense, debt	$ 5,500,000
Amortization of debt discount (premium)	2,700,000
Interest expense	$ 2,800,000
Repayments of Convertible Debt		$ 0	$ 4,459,000
Gain on extinguishment of Convertible Senior Notes			$ 421,000
Convertible Debt [Member] | Senior 3 Point 25 Percent Convertible Notes Due 2020 [Member]
Debt Instrument [Line Items]
Convertible Senior Notes, face amount					$ 172,500,000.0
Senior Credit Facility, applicable margin	3.25%	3.25%
Debt issuance cost					5,100,000
Deferred financing costs					$ (4,200,000)
Remaining amortization period of discount on the liability component		3 years 6 months		4 years	6 years
Adjustments to additional paid in capital		$ 900,000
Convertible Senior Notes, conversion ratio		31.1891
Convertible Senior Notes, conversion price (in usd per share) | $ / shares	$ 32.06	$ 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		$ 5,500,000
Amortization of debt discount (premium)		2,800,000
Interest expense		$ 2,700,000
Converted instrument, rate		100.00%
Interest rate	6.90%	6.90%
Convertible Senior Notes, fair value disclosures					$ 141,900,000
Carrying value of equity component, net of issuance costs	$ 29,211,000	$ 29,211,000		$ 29,211,000		$ 30,700,000
Repurchase of Convertible Debt		5,200,000
Repayments of Convertible Debt		4,500,000
Repayments of Debt	4,400,000
Equity component of convertible debt,		500,000
Gain on extinguishment of Convertible Senior Notes	400,000
Other Current Assets [Member] | Convertible Debt [Member] | Senior 3 Point 25 Percent Convertible Notes Due 2020 [Member]
Debt Instrument [Line Items]
Deferred financing costs	$ (2,425,000)	$ (2,425,000)		$ (2,753,000)