Supplemental Cash Flow Information - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Apr. 17, 2017	Apr. 14, 2017	Mar. 28, 2017	Mar. 17, 2017	Dec. 31, 2016	Jun. 30, 2016
Supplemental Cash Flow Information [Line Items]
Restricted cash	$ 11,924					$ 1,917	$ 1,811
Certificate of deposits value	$ 1,880
Interest rate of convertible notes	6.25%
Certificates of Deposit [Member]
Supplemental Cash Flow Information [Line Items]
Restricted cash	$ 1,917
6.25% Convertible Notes Due 2018 [Member]
Supplemental Cash Flow Information [Line Items]
Convertible notes	$ 10,044	$ 10,044		$ 94,000		$ 94,000
Interest rate of convertible notes	6.25%		6.25%	6.25%	6.25%
ASU 2016-18 [Member]
Supplemental Cash Flow Information [Line Items]
Net change in restricted cash	$ 13