Stockholders' Equity - Changes in Stockholders' Equity (Detail) - USD ($) $ in Thousands	2 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at January 1, 2017				$ 322,087
Net income for the nine months ended September 30, 2017		$ 3,727	$ 4,058	6,078	$ 10,953
Cash dividends declared				(7,776)
Common stock repurchase program	$ (10,000)			(10,024)
Amortization of stock based compensation				2,815
Other				189
Balance at September 30, 2017		$ 313,369		$ 313,369