Non-Vested Stock Units (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share Based Compensation [Line Items]
Forward Interest Rate, Minimum	1.46%
Forward Interest Rate, Maximum	1.93%
Non-Vested Stock [Member]
Share Based Compensation [Line Items]
Non-vested Stock Outstanding, Beginning Balance	917,959
Non-vested Stok Granted, Number of Shares	93,256
Non-vested Stock Vested, Number of Shares	(355,396)
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares	(154,931)
Non-vested Stock Outstanding, Ending Balance	500,888	917,959
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value	$ 15.17
Non-vested Stock Granted, Weighted Average Grant Date Fair Value	28.48	$ 16.38	$ 10.91
Non-vested Stock Vested, Weighted Average Grant Date Fair Value	14.69
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value	14.34
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value	$ 18.24	15.17
Non-Vested Stock Units - Service-Based and Performance-Based [Member]
Share Based Compensation [Line Items]
Non-vested Stok Granted, Number of Shares	154,732
Non-vested Stock Vested, Number of Shares	0
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares	(3,669)
Non-vested Stock Outstanding, Ending Balance	151,063
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value	$ 0.00
Non-vested Stock Granted, Weighted Average Grant Date Fair Value	39.54
Non-vested Stock Vested, Weighted Average Grant Date Fair Value	0
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value	43.63
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value	$ 39.44	$ 0.00
Non-Vested Stock Units - Service-Based and Market-Based [Member]
Share Based Compensation [Line Items]
Non-vested Stock Outstanding, Beginning Balance	225,745
Non-vested Stok Granted, Number of Shares	0
Non-vested Stock Vested, Number of Shares	0
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares	(61,211)
Non-vested Stock Outstanding, Ending Balance	164,534	225,745
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value	$ 10.51
Non-vested Stock Granted, Weighted Average Grant Date Fair Value	0
Non-vested Stock Vested, Weighted Average Grant Date Fair Value	0
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value	10.51
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value	$ 10.51	$ 10.51
Forward Interest Rate, Minimum			0.327%
Forward Interest Rate, Maximum			1.46%
Expected Volatility			54.38%
Requisite Service Period			3 years
Fair Value			$ 10.51
Non Vested Stock Units Service [Member]
Share Based Compensation [Line Items]
Non-vested Stock Outstanding, Beginning Balance	0
Non-vested Stok Granted, Number of Shares	186,314
Non-vested Stock Vested, Number of Shares	0
Non-vested Stock Canceled, Forfeited or Expired, Number of Shares	(2,982)
Non-vested Stock Outstanding, Ending Balance	183,332	0
Non-vested Stock Outstanding, Beginning Balance, Weighted Average Grant Date Fair Value	$ 0.00
Non-vested Stock Granted, Weighted Average Grant Date Fair Value	37.98
Non-vested Stock Vested, Weighted Average Grant Date Fair Value	0
Non-vested Stock Canceld, Forfeited or Expired, Weighted Average Grant Date Fair Value	43.63
Non-vested Stock Outstanding, Ending Balance, Weighted Average Grant Date Fair Value	$ 37.89	$ 0.00