Earnings Per Share - Additional Information (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Apr. 14, 2017	Mar. 28, 2017	Mar. 17, 2017
Number of shares excluded from computation of earnings per share [Line Items]
Interest rate of convertible notes	6.25%		6.25%
Antidilutive securities excluded from computation of earnings per share, amount	1,957		1,957
6.25% Convertible Notes Due 2018 [Member]
Number of shares excluded from computation of earnings per share [Line Items]
Interest rate of convertible notes	6.25%		6.25%		6.25%	6.25%	6.25%
Convertible Notes Payable [Member]
Number of shares excluded from computation of earnings per share [Line Items]
Anti-dilutive shares excluded from calculation	2,502		5,714
Convertible Notes Payable [Member] | 6.25% Convertible Notes Due 2018 [Member]
Number of shares excluded from computation of earnings per share [Line Items]
Anti-dilutive shares excluded from calculation		9,143		9,298