The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Condensed Financial Information of Parent Company - Condensed Statements of Earnings (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Other expense, net									$ (179,911)	$ (140,753)	$ (136,740)
Net earnings	$ 43,159	$ 38,558	$ 35,373	$ 34,913	$ 17,851	$ 29,683	$ 28,373	$ 28,504	152,003	104,411	101,429
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Excess in net earnings of subsidiaries									78,601	50,253	55,192
Dividends from the Bank									77,800	57,000	49,000
Other expense, net									(4,398)	(2,842)	(2,763)
Net earnings									$ 152,003	$ 104,411	$ 101,429