Debt - Additional Information (Detail)			3 Months Ended		6 Months Ended
	May 10, 2017 USD ($)	Feb. 01, 2016 USD ($) extension_option	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)	Aug. 05, 2015 USD ($)
Line of Credit Facility [Line Items]
Gross proceeds from issuance of senior notes					$ 0	$ 100,000,000
Payments on the mortgage notes payable					0	95,022,000
Interest expense			$ 6,219,000	$ 5,440,000	12,098,000	11,301,000
Amortization of deferred financing costs			600,000	$ 600,000	1,100,000	1,100,000
Interest payable			$ 1,700,000		1,700,000		$ 1,300,000
Loss on the extinguishment of debt					7,600,000
Write-off of deferred financing costs					$ 4,200,000	$ 300,000
Senior Unsecured Notes [Member] | 5.25% Senior Notes due 2025 [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount	$ 300,000,000
Interest rate, stated percentage	5.25%
Gross proceeds from issuance of senior notes	$ 300,000,000
Net proceeds from issuance of senior notes	$ 294,000,000
Debt instrument, redemption price, percentage	100.00%
Debt instrument, redemption price, percentage upon change of control	101.00%
Senior Unsecured Notes [Member] | 5.25% Senior Notes due 2025 [Member] | Debt Instrument, Redemption, Period One [Member]
Line of Credit Facility [Line Items]
Debt instrument, redemption price, percentage	105.25%
Senior Unsecured Notes [Member] | 5.25% Senior Notes due 2025 [Member] | Debt Instrument, Redemption, Period One [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Debt instrument, redemption price, percentage of principal amount	40.00%
Senior Unsecured Notes [Member] | 5.25% Senior Notes due 2025 [Member] | Debt Instrument, Redemption, Period One [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Percentage of aggregate principal amount of notes outstanding	60.00%
Senior Unsecured Notes [Member] | 5.875% Senior Notes due 2021 [Member]
Line of Credit Facility [Line Items]
Interest rate, stated percentage	5.875%
Payment for redemption of senior notes	$ 260,000,000
Debt instrument, redemption price, percentage	102.938%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity								$ 300,000,000.0
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage					0.25%
Line of credit facility, facility fee percentage					0.30%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					1.40%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					2.40%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Line of credit facility, commitment fee percentage					0.15%
Line of credit facility, facility fee percentage					0.125%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					0.75%
Credit facility [Member] | Unsecured Revolving Credit Facility [Member] | Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					1.75%
Credit facility [Member] | Revolving Credit Facility As Amended [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity		$ 400,000,000.0
Line of credit facility, increase to borrowing capacity		100,000,000.0
Line of credit facility, increase to uncommitted incremental facility		50,000,000.0
Line of credit facility, uncommitted incremental facility limit		$ 250,000,000.0
Number of extension options | extension_option		2
Line of credit facility, extension period		6 months
Credit facility [Member] | Revolving Credit Facility As Amended [Member] | Maximum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					1.60%
Credit facility [Member] | Revolving Credit Facility As Amended [Member] | Maximum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					2.60%
Credit facility [Member] | Revolving Credit Facility As Amended [Member] | Minimum [Member] | Base Rate [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					0.95%
Credit facility [Member] | Revolving Credit Facility As Amended [Member] | Minimum [Member] | LIBOR [Member]
Line of Credit Facility [Line Items]
Debt instrument, basis spread					1.95%
Credit facility [Member] | Senior unsecured term loan [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity		$ 100,000,000.0
Line of credit facility, prepayment premium in first year		2.00%
Line of credit facility, prepayment premium in second year		1.00%
Mortgage notes payable [Member]
Line of Credit Facility [Line Items]
Payments on the mortgage notes payable		$ 95,000,000