Description of Company and Basis of Presentation - Narrative (Details) $ / shares in Units, $ in Millions				12 Months Ended
	Feb. 24, 2017 shares	Feb. 15, 2017 USD ($) $ / shares shares	Feb. 08, 2017	Dec. 31, 2017 employee segment branch
Class of Stock [Line Items]
Number of employees | employee				3,700
Number of branch locations | branch				200
Number of reportable segments | segment				2
Stock split, conversion ratio			29,974.239
Proceeds from issuance of IPO | $		$ 164.0
Repayments of borrowings outstanding | $		$ 164.0
Pro forma stock split ratio				29,974.239
IPO
Class of Stock [Line Items]
Number of shares issued in transaction (in shares) | shares		12,800,000
Offering price (in dollars per share) | $ / shares		$ 14.00
Subsidiaries | Over-Allotment Option
Class of Stock [Line Items]
Number of shares issued in transaction (in shares) | shares	1,920,000