Stockholders' Equity - Diluted Earnings per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								6 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Net income (loss) attributable to common stockholders	$ (7,534)	$ 7,180	$ 6,146	$ 9,986	$ 8,097	$ 11,277	$ 12,671	$ 9,444	$ 16,132	$ 22,115	$ 23,312	$ 33,392	$ 15,778	$ 41,489	$ (2,269)
Weighted average number of common shares outstanding (in shares)	30,758	30,581	30,547	30,513	30,447	30,219	30,219	30,219	30,530	30,219	30,547	30,219	30,602	30,277	29,942
Dilutive effect of restricted stock grants after application of the treasury stock method (in shares)													221	310	0
Dilutive shares outstanding (in shares)	30,758	30,852	30,824	30,694	30,543	30,638	30,513	30,574	30,731	30,543	30,829	30,575	30,823	30,587	29,942
Basic (in dollars per share)	$ (0.24)	$ 0.23	$ 0.20	$ 0.33	$ 0.27	$ 0.37	$ 0.42	$ 0.31	$ 0.53	$ 0.73	$ 0.76	$ 1.11	$ 0.52	$ 1.37	$ (0.08)
Diluted (in dollars per share)	$ (0.24)	$ 0.23	$ 0.20	$ 0.33	$ 0.26	$ 0.37	$ 0.42	$ 0.31	$ 0.52	$ 0.72	$ 0.76	$ 1.09	$ 0.51	$ 1.36	$ (0.08)