Share-Based Employee Compensation - Summary of Total Number of SARs Granted (Detail) - Stock Appreciation Rights (SARs) shares in Thousands	12 Months Ended
	Dec. 31, 2016 $ / shares shares
Number of Share units
Nonvested number of Units, beginning balance | shares	498
Granted, number of units | shares	0
Exercised, number of units | shares	(448)
Forfeited, number of units | shares	0
Vested, number of units, ending balance | shares	50
Weighted Average Grant Date Fair Value
Nonvested weighted Average Grant Date Fair Value, beginning balance (in dollars per unit) | $ / shares	$ 6.51
Granted, weighted average grant date fair value (in dollars per unit) | $ / shares	0.00
Exercised, weighted average exercise price (in dollars per unit) | $ / shares	6.51
Forfeited, weighted average grant date fair value (in dollars per unit) | $ / shares	0.00
Vested, Weighted Average Grant Date Fair Value, ending balance (in dollars per unit) | $ / shares	$ 6.48