Description of Business and Accounting Policies - Reconciliation of Number of Shares Used in Calculation of Basic and Diluted Per Share Amounts (Detail) - shares shares in Thousands	3 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	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Weighted average common shares outstanding, basic	12,997	12,934	12,855	12,795	12,755	12,721	12,697	12,673	12,896	12,712
Weighted average common shares outstanding, diluted	12,997	12,934	12,855	12,795	12,755	12,721	12,697	12,673	12,896	12,712