Earnings per Share Data (Detail) - Basic Earnings Per Share - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Basic weighted-average shares	23,140	22,814	23,034	22,728
Conversion of unsecured loan notes	0	0	0	0
Unexercised options and unvested RSUs	0	0	0	0
Diluted weighted-average shares	23,140	22,814	23,034	22,728