Debt - $200 Million Term Loan A - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Net proceeds from credit facility		$ 200,000
$200 Million Term Loan A [Member]
Debt Instrument [Line Items]
Maturity date for credit facility		May 23, 2022
Debt Instrument, description of interest rate		(i) LIBOR plus the applicable margin ranging from 1.50% to 2.35%, dependent upon the Company's funded debt to total asset value ratio (as defined in the Amended Credit Agreement) or (ii) a base rate as set in the Amended Credit Agreement.
Spread rate added to LIBOR		1.50%
Net proceeds from credit facility	$ 194,600
$200 Million Term Loan A [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread rate added to LIBOR		1.50%
$200 Million Term Loan A [Member] | Maximum [Member]
Debt Instrument [Line Items]
Spread rate added to LIBOR		2.35%