Shareholders' Equity - Additional Information (Detail) - Common Stock [Member] $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) $ / shares shares	Jun. 30, 2017 $ / shares shares
Shareholders Equity [Line Items]
Issuance of common stock | shares	500	500
Common stock price per share | $ / shares	$ 35.55	$ 35.55
Cash proceeds from sale of common stock	$ 17,775
Stock issuance cost	$ 72