Shareholders' Equity - Additional Information (Detail) - Jun. 30, 2015 - USD ($) $ / shares in Units, shares in Thousands	Total
Equity [Abstract]
Share repurchase program, authorized amount	$ 100,000,000
Stock repurchase program, term (in years)	3 years
Stock repurchase program, expiring date	2017-02
Stock repurchased and retired, shares	220
Stock repurchased and retired, value	$ 7,400,000
Stock repurchase program, average price in USD per share	$ 33.82
Stock repurchase program, remaining authorized repurchase amount	$ 82,600,000