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Stockholders' Equity - Summary of Changes in Common Shares Available for Awards under Omnibus Incentive Plan and Predecessor Plans (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]      
Restricted stock shares issued for new awards (20,587) (71,893) (101,062)
Restricted stock shares forfeited 89,699 185,056  
2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Number of shares available, beginning of year 7,694,739 8,775,994 5,676,699
Restricted stock shares issued for new awards (481,834) (419,844) (572,089)
Shares withheld for taxes 696,131   69,821
Number of shares available, end of year 6,082,001 7,694,739 8,775,994
Omnibus Incentive Plan      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Newly registered shares under Omnibus Incentive Plan     4,250,000
2012 President and COO Four-year Incentive Compensation [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards (325,000)    
2013 Three-year PSU Awards [member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards (1,074,017)    
2012 Three-year PSU Awards [member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards   (442,985)  
2011 Three-year PSU Awards [member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards     (145,597)
2002 Directors Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Director shares granted and issued (18,022) (20,246) (21,128)
Director units granted and deferred (17,447) (925) (20,444)
Restricted Stock [Member] | 2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares forfeited 87,886 185,056 106,220
Restricted Stock Units (RSUs) [Member] | 2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards (428,595) (300,085) (431,987)
Restricted stock shares forfeited 29,774 38,100 9,800
Restricted Stock SLO Awards [Member] | 2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards     (96,773)
Restricted Stock Units RSU SLO Awards [Member] | 2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares issued for new awards (81,614) (134,078) (48,528)
SLO Awards [Member] | 2005 Contingent Stock Plan [Member]      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Restricted stock shares forfeited   13,752