Capital Stock (Detail) - shares	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Stockholders Equity Note [Abstract]
Beginning balance	169,316,460	168,628,177
SARs exercised	0	77,002
Restricted stock grants	132,237	335,103
Restricted stock units vested	238,238	252,507
Treasury shares issued	9,720	23,671
Ending balance	169,696,655	169,316,460