Contingencies - Additional Information (Detail) $ in Thousands				3 Months Ended
	Jul. 25, 2018 Claim	Jun. 08, 2018 USD ($)	Feb. 02, 2018 Plaintiff	Jun. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jan. 21, 2016 Member	Mar. 05, 2008 Claim
Loss Contingencies [Line Items]
Settlement agreement date			February 2, 2018
Loss Contingency Damages Sought Percentage Of Total Charge			44.00%
Number of plaintiffs | Plaintiff			1,169
Estimated settlement reserve				$ 8,100
Reserve recorded during the current period				4,900
Loss contingency, initial payment		$ 3,000
Number of individuals WCI file motion to compel arbitration | Member						1,100
Number of arbitration claims filed | Claim	325
Attorney's Fees and Costs [Member]
Loss Contingencies [Line Items]
Estimated settlement reserve				4,900
Reserve recorded during the current period				1,100
Court awarded settlement amount		4,900
Maximum [Member]
Loss Contingencies [Line Items]
Estimated settlement reserve		11,100
Maximum [Member] | Attorney's Fees and Costs [Member]
Loss Contingencies [Line Items]
Litigation settlement awarded amount		8,000
Minimum [Member] | Attorney's Fees and Costs [Member]
Loss Contingencies [Line Items]
Litigation settlement awarded amount		$ 3,750
Surrett [Member]
Loss Contingencies [Line Items]
Number of alleged claims for equitable relief | Claim							2
Other Accrued Expenses [Member]
Loss Contingencies [Line Items]
Accrual for legal fees and settlements				$ 13,800	$ 8,700