Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018	[1]	Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017	[1]	Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Revenues	$ 25,721		$ 40,545		$ 57,831		$ 42,428		$ 24,613		$ 24,706		$ 52,231		$ 38,830		$ 166,525	[2]	$ 140,380	[2]	$ 105,481
Gross profit (loss)	3,083		7,729		(26,082)		7,905		3,027		5,070		17,420		12,467		(7,365)	[2]	37,984	[2]	31,086
Operating expenses	6,980		8,098		11,346		8,819		12,664		3,594		3,520		3,074		35,243	[2]	22,852	[2]	12,139
Operating income (loss)	(3,897)		(369)		(37,428)		(914)		(9,637)		1,476		13,900		9,393		(42,608)	[2]	15,132	[2]	18,947
Other expense	(4,139)		(4,064)		(3,346)		(3,206)		(2,958)		(24)		(61)		(85)		(14,755)	[2]	(3,128)	[2]	(1,682)
Income (loss) before income taxes	(8,036)		(4,433)		(40,774)		(4,120)		(12,595)		1,452		13,839		9,308		(57,363)	[2]	12,004	[2]	17,265
Income tax expense (benefit)	71		9,447		(10,158)		(1,064)		(7,389)		(652)		5,314		3,574		(1,704)	[2]	847	[2]	6,628
Net income (loss)	$ (8,107)		$ (13,880)		$ (30,616)		$ (3,056)		$ (5,206)		$ 2,104		$ 8,525		$ 5,734		$ (55,659)		$ 11,157		$ 10,637
Net income per common share - Basic	$ (0.19)	[2]	$ (0.33)	[2]	$ (0.72)	[2]	$ (0.07)	[2]	$ (0.12)	[2]	$ 0.05	[2]	$ 0.21	[2]	$ 0.14	[2]	$ (1.31)	[2]	$ 0.27	[2]	$ 0.31
Net income per common share - Diluted	$ (0.19)	[2]	$ (0.33)	[2]	$ (0.72)	[2]	$ (0.07)	[2]	$ (0.12)	[2]	$ 0.05	[2]	$ 0.20	[2]	$ 0.13	[2]	$ (1.31)	[2]	$ 0.26	[2]	$ 0.30
Weighted average number of shares - basic	42,600,898		42,530,476		42,403,140		42,403,029		42,216,987		41,869,528		41,567,848		41,507,941		42,484,972	[2]	41,764,230	[2]	34,104,476
Weighted average number of shares outstanding - diluted	42,600,898		42,530,476		42,403,140		42,403,029		42,216,987		43,463,982		43,550,226		43,503,889		42,484,972	[2]	42,766,843	[2]	35,416,910

[1] As discussed previously, the fourth quarter 2017 results include the results of ARI subsequent to the acquisition on October 10, 2017.

[2] The sum of the net earnings per share may not add up to the full year amount due to rounding and because the quarterly calculations are based on varying numbers of shares outstanding.