Office Closing and Termination Costs - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Restructuring Cost And Reserve [Line Items]
Termination costs	$ 136,000	$ (77,000)	$ 8,400,000	$ 303,000	$ 6,290,000
Stock-based compensation expense (gain)					1,720,000
Building lease				303,000	3,156,000	$ 3,200,000
Office closing costs					$ 1,414,000
Memorial
Restructuring Cost And Reserve [Line Items]
Termination costs				0
Office closing costs				$ 0
Oklahoma City Restructuring
Restructuring Cost And Reserve [Line Items]
Additional accruals for severance costs						275,000
Stock-based compensation expense (gain)						$ 608,000