Basis of Presentation - Additional Information (Details) $ / shares in Units, $ in Thousands					3 Months Ended
	Jan. 02, 2017 USD ($)	Sep. 15, 2016 USD ($) $ / shares shares	Aug. 15, 2016 USD ($)	Jun. 28, 2016 shares	Mar. 31, 2017 Branch shares	Mar. 31, 2016 shares	Dec. 31, 2016 shares	Jul. 31, 2016 shares
Class Of Stock [Line Items]
Description of stock split					the Company declared a 100-for-1 stock split, increasing the number of issued and authorized shares from 171,800 to 17,180,000 and 250,000 to 25,000,000, respectively.
Stock split ratio				0.01
Common stock, shares issued					24,154,323		24,107,660
Common stock, shares authorized					75,000,000		25,000,000
Dilutive instruments outstanding					472,554	0
ASC 860-50-35, Transfers and Servicing
Class Of Stock [Line Items]
Adjustment to retained earnings | $	$ 615
Pro forma
Class Of Stock [Line Items]
Effective tax rate					37.32%
Initial Public Offering
Class Of Stock [Line Items]
Common stock sold and issued, shares		6,764,704
Common stock sold and issued, price per share | $ / shares		$ 19
Proceeds from issuance of common stock, net of offering costs | $		$ 115,525
Distribution to majority shareholder from net proceeds | $		55,000
Repayments of aggregate principal amount of subordinated notes from net proceeds | $		$ 10,075	$ 10,075
Minimum
Class Of Stock [Line Items]
Common stock, shares issued				171,800
Common stock, shares authorized				250,000				25,000,000
Maximum
Class Of Stock [Line Items]
Common stock, shares issued				17,180,000
Common stock, shares authorized				25,000,000				75,000,000
FirstBank
Class Of Stock [Line Items]
Number of bank branches | Branch					45