Summary of Significant Accounting Policies and Practices - Amounts Used In Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	7 Months Ended		12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	May. 31, 2015	May. 31, 2014	May. 31, 2013
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Weighted-average number of basic shares outstanding	20,852	20,593	20,500	20,439	20,203
Stock options, stock units and performance awards	260		419	633	759
Conversion of non-controlling interest	313		732	213	204
Total shares and dilutive securities	21,425	21,907	21,651	21,285	21,166