Share-Based Compensation - Schedule of Information with Respect to all Outstanding Restricted Stock and Restricted Stock Units (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance of Outstanding Shares	757,871	[1]	598,892		760,183
Granted, Shares	1,555,828		808,898	[1]	318,940
Vested, Shares	(381,850)	[2]	(237,578)		(271,778)
Forfeited, Shares	(219,645)		(412,341)		(208,453)
Ending balance of Outstanding Shares	1,712,204		757,871	[1]	598,892
Restricted Stock Shares [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance of Outstanding Shares			42,752		221,562
Vested, Shares			(39,969)		(136,133)
Forfeited, Shares			(2,783)		(42,677)
Ending balance of Outstanding Shares					42,752
Beginning balance of Outstanding, Weighted Average Grant-Date Fair Value Per Share			$ 21.63		$ 22.19
Vested, Weighted Average Grant-Date Fair Value Per Share			21.62		22.94
Forfeited, Weighted Average Grant-Date Fair Value Per Share			$ 21.80		20.87
Ending balance of Outstanding, Weighted Average Grant-Date Fair Value Per Share					$ 21.63
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Beginning balance of Outstanding Shares	757,871	[1]	556,140		538,621
Granted, Shares	1,555,828		808,898	[1]	318,940
Vested, Shares	(381,850)	[2]	(197,609)		(135,645)
Forfeited, Shares	(219,645)		(409,558)		(165,776)
Ending balance of Outstanding Shares	1,712,204		757,871	[1]	556,140
Beginning balance of Outstanding, Weighted Average Grant-Date Fair Value Per Share	$ 5.55	[1]	$ 7.35		$ 8.30
Granted, Weighted Average Grant-Date Fair Value Per Share	4.58		5.29	[1]	6.57
Vested, Weighted Average Grant-Date Fair Value Per Share	5.98	[2]	7.94		8.61
Forfeited, Weighted Average Grant-Date Fair Value Per Share	5.06		6.33		7.90
Ending balance of Outstanding, Weighted Average Grant-Date Fair Value Per Share	$ 4.63		$ 5.55	[1]	$ 7.35

[1] The total granted awards during 2015 and total outstanding balance as of December 31, 2015 includes an adjustment of 163,566 restricted stock units. These units were previously recorded in the summary table of restricted stock units settled in cash due to the potential for cash settlement upon an involuntary, not for cause termination.

[2] The total vested awards include 9.2 thousand of vested restricted stock units settled in cash. As a result of the termination provision for certain awards, in the event of an involuntary not-for-cause termination of employment by the Company certain termination scenarios allow for cash-settlement.