Comprehensive Income and Accumulated Other Comprehensive Income - Schedule of Changes in Accumulated Other Comprehensive Income (AOCI) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	$ 468,366	$ 462,796	$ 438,816	$ 430,215
Other comprehensive income (loss) before reclassification	(1,614)	1,316	(4,210)	8,317
Amounts reclassified from accumulated other comprehensive income	(262)	(582)	(1,823)	(616)
Net current period other comprehensive income (loss)	(1,876)	734	(6,033)	7,701
Ending Balance	480,156	481,910	480,156	481,910
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance	16,862	19,178	21,019	12,211
Ending Balance	$ 14,986	$ 19,912	$ 14,986	$ 19,912

Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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+ Details