Segment Information - Results of Operations and Selected Financial Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Segment Reporting Information [Line Items]
Net interest income	$ 77,208	$ 68,792	$ 151,281	$ 135,695
Noninterest income	32,082	34,077	67,227	66,078
Income before taxes	25,306	43,828	53,556	84,842
Total Assets	9,612,453		9,612,453		$ 8,565,758
Operating Segments [Member] \| Metropolitan Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	22,310	21,438	44,494	42,791
Noninterest income	4,571	4,635	9,271	8,844
Income before taxes	3,613	14,866	14,026	30,235
Total Assets	3,035,989		3,035,989		2,806,021
Operating Segments [Member] \| Community Banks [Member]
Segment Reporting Information [Line Items]
Net interest income	43,917	44,775	88,415	88,182
Noninterest income	13,841	16,243	29,694	31,128
Income before taxes	15,532	30,041	39,968	58,086
Total Assets	5,703,770		5,703,770		4,998,247
Operating Segments [Member] \| Pegasus Bank [Member]
Segment Reporting Information [Line Items]
Net interest income	4,976		10,584
Noninterest income	121		252
Income before taxes	1,345		2,943
Total Assets	774,939		774,939		738,351
Operating Segments [Member] \| Other Financial Services [Member]
Segment Reporting Information [Line Items]
Net interest income	5,905	1,411	7,488	2,582
Noninterest income	9,328	10,105	20,218	19,978
Income before taxes	7,786	5,572	13,545	10,071
Total Assets	938,034		938,034		102,442
Operating Segments [Member] \| Executive, Operations & Support [Member]
Segment Reporting Information [Line Items]
Net interest income	100	1,168	300	2,140
Noninterest income	25,774	37,917	53,257	73,438
Income before taxes	18,232	27,590	27,635	52,613
Total Assets	248,390		248,390		950,920
Eliminations [Member]
Segment Reporting Information [Line Items]
Noninterest income	(21,553)	(34,823)	(45,465)	(67,310)
Income before taxes	(21,202)	$ (34,241)	(44,561)	$ (66,163)
Total Assets	$ (1,088,669)		$ (1,088,669)		$ (1,030,223)

Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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