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Equity-Based Compensation - The Amended Director Plan Additional Information (Detail) - $ / shares	1 Months Ended		3 Months Ended				6 Months Ended
	Jun. 30, 2015	Jan. 31, 2015	Jun. 30, 2016	Mar. 31, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, vested			81,391	657,317	63,017	644,247
Number of shares, granted			112,397	434,283	140,416	441,256
Weighted Average Fair Value, Granted (in dollars per share)			$ 9.33	$ 8.44	$ 13.17	$ 16.21
Number of shares, forfeited			7,500	588,819		43,660
Deferred stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option shares, granted							22,500
Non-Management Director Compensation Plan \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards vesting period							6 months
Non-Management Director Compensation Plan \| Deferred stock units \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards vesting period							1 year
Number of shares, vested							7,500
Non-Management Director Compensation Plan \| Deferred stock units \| Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock awards vesting period							2 years
Number of shares, vested							15,000
Prior Director Plan \| Deferred stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of non-option shares, granted							7,500
Non Management Directors Director Plan, Retainer Fee, First Half of 2015 \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted		18,200
Weighted Average Fair Value, Granted (in dollars per share)		$ 16.10
Non Management Directors Director Plan, Retainer Fee, June 12, 2015 through June 12, 2016 \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	50,416
Weighted Average Fair Value, Granted (in dollars per share)	$ 13.17
Non Management Directors Director Plan, Triennial Service Awards \| Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	90,000
Weighted Average Fair Value, Granted (in dollars per share)	$ 13.17
Non Management Directors Director Plan, Triennial Service Awards \| Restricted Stock \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	30,000
Non Management Directors Director Plan, Triennial Service Awards \| Restricted Stock \| Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	60,000
Non Management Directors Director Plan, Triennial Service Awards \| Deferred stock units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	90,000
Weighted Average Fair Value, Granted (in dollars per share)	$ 13.17
Non Management Directors Director Plan, Triennial Service Awards \| Deferred stock units \| Tranche One
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	30,000
Number of shares, forfeited	15,000
Non Management Directors Director Plan, Triennial Service Awards \| Deferred stock units \| Tranche Two
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, granted	45,000