Stock Plans - Share Based Compensation Activity (Detail) - Omnibus Incentive 2016 Plan [Member] - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding Balance, Shares	206,509
Stock options granted	0	0	0
Exercised, Shares	(186,718)
Canceled, Shares	(341)
Outstanding Balance, Shares	19,450	206,509
Exercisable Balance, Shares	19,450
Outstanding Balance, Weighted Average Exercise Price	$ 29.55
Granted, Weighted Average Exercise Price	0
Exercised, Weighted Average Exercise Price	30.38
Canceled, Weighted Average Exercise Price	46.03
Outstanding Balance, Weighted Average Exercise Price	21.31	$ 29.55
Exercisable Balance, Weighted Average Exercise Price	$ 21.31
Restricted Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested shares balance, Shares	540,339
Granted, Shares	182,916
Vested, Shares	(220,863)
Canceled, Shares	(400)
Nonvested shares balance, Shares	501,992	540,339
Nonvested shares balance, Weighted Average Grant-Date Fair-Value	$ 43.05
Granted, Weighted Average Grant-Date Fair-Value	47.71	$ 57.21	$ 41.61
Vested, Weighted Average Grant-Date Fair-Value	38.79
Canceled, Weighted Average Grant-Date Fair-Value	48.40
Nonvested shares balance, Weighted Average Grant-Date Fair-Value	$ 46.52	$ 43.05