Stockholders' Equity, Initial Pubic Offering (Details) - USD ($) $ / shares in Units, $ in Millions	May 17, 2017	Dec. 06, 2016	Aug. 02, 2016	Jul. 28, 2016
Class of Stock [Line Items]
Share price (in dollars per share)	$ 33.00	$ 27.50
Stock issued			7,590,000
Common stock sold by selling stockholders (in shares)	4,557,774	3,864,000	2,590,000
Net proceeds from IPO, net of discounts, commissions and other offering costs			$ 72.8
IPO [Member]
Class of Stock [Line Items]
Share price (in dollars per share)			$ 16.00	$ 16.00
Stock issued			5,000,000
Underwriters Option [Member]
Class of Stock [Line Items]
Stock issued			990,000
Common stock sold by selling stockholders (in shares)	594,492	504,000