v3.10.0.1

Earnings Per Share - Summary of Reconciliation of Numerators and Denominators Used in Basic and Diluted Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Class A Common Stock [Member]
Numerator:
Allocation of net (loss) income	$ 1,006	$ 5,787	$ (14,472)	$ 8,066
Denominator:
Weighted-average shares outstanding	22,717	21,756	22,673	21,669
Basic (loss) earnings per share	$ 0.04	$ 0.27	$ (0.64)	$ 0.37
Numerator:
Allocation of net (loss) income	$ 1,006	$ 5,787	$ (14,472)	$ 8,066
Denominator:
Number of shares used in basic computation	22,717	21,756	22,673	21,669
Weighted-average shares effect of dilutive securities:
Director and employee stock options	178	461		778
Number of shares used in diluted computation	22,895	22,217	22,673	22,447
Diluted (loss) earnings per share	$ 0.04	$ 0.26	$ (0.64)	$ 0.36
Class B Common Stock [Member]
Numerator:
Allocation of net (loss) income	$ 200	$ 1,322	$ (3,290)	$ 1,829
Denominator:
Weighted-average shares outstanding	5,577	5,577	5,577	5,577
Basic (loss) earnings per share	$ 0.04	$ 0.24	$ (0.59)	$ 0.33
Numerator:
Allocation of net (loss) income	$ 200	$ 1,322	$ (3,290)	$ 1,829
Denominator:
Number of shares used in basic computation	5,577	5,577	5,577	5,577
Weighted-average shares effect of dilutive securities:
Number of shares used in diluted computation	5,577	5,577	5,577	5,577
Diluted (loss) earnings per share	$ 0.04	$ 0.24	$ (0.59)	$ 0.33

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- Definition

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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