Shareholders' Equity - Additional Information (Detail) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	1 Months Ended	6 Months Ended
	Feb. 28, 2014	Jun. 30, 2014
Equity [Abstract]
Share repurchase program, authorized amount	$ 100,000,000
Stock repurchase program, term (in years)	3 years
Stock repurchase program, expiration date		2017-02
Stock repurchased and retired, shares		277
Stock repurchased and retired, value		9,500,000
Stock repurchase program, average price in USD per share		$ 34.30
Stock repurchase program, remaining authorized repurchase amount		$ 90,500,000