Share Repurchase Programs (Detail) - USD ($)	3 Months Ended	77 Months Ended	86 Months Ended
Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2021	Aug. 31, 2014
Equity [Abstract]
Stock repurchase program, authorized amount				$ 50,000,000
Purchase of common stock, shares (in shares)	0		1,416,587
Common stock repurchased		$ 22,000,000

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration