Debt - Additional Information (Detail)			3 Months Ended
	Feb. 01, 2016 USD ($) extension_option	May 30, 2014 USD ($)	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	Aug. 05, 2015 USD ($)
Line of Credit Facility [Line Items]
Payments on the mortgage notes payable			$ 0	$ 95,022,000
Interest expense			5,879,000	6,187,000
Amortization of deferred financing costs			600,000	600,000
Write-off of deferred financing costs			0	$ 326,000
Interest payable			5,100,000		$ 1,300,000
Unsecured Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit			27,000,000		95,000,000
Senior unsecured term loan [Member]
Line of Credit Facility [Line Items]
Line of credit			$ 99,445,000		$ 99,422,000
Senior Unsecured Notes [Member]
Line of Credit Facility [Line Items]
Debt instrument, face amount		$ 260,000,000.0
Gross proceeds from issuance of senior notes		260,000,000
Net proceeds from issuance of senior notes		$ 253,000,000
Debt instrument, maturity date		Jun. 01, 2021
State interest rate		5.875%
Frequency of interest payable on notes		Interest on the Notes is payable on June 1 and December 1 of each year, beginning on December 1, 2014.
Debt instrument, redemption price, percentage upon change of control		101.00%
Senior Unsecured Notes [Member] | Debt Instrument, Redemption, Period One [Member]
Line of Credit Facility [Line Items]
Debt instrument, end of initial redemption period		Jun. 01, 2017
Debt instrument, redemption price, percentage		100.00%
Senior Unsecured Notes [Member] | Debt Instrument, Redemption, Period One [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Percentage of aggregate principal amount of notes outstanding		65.00%
Senior Unsecured Notes [Member] | Debt Instrument, Redemption, Period One [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Redeemable percentage of aggregate principal amount of notes		35.00%
Senior Unsecured Notes [Member] | Ensign [Member]
Line of Credit Facility [Line Items]
Approximate amount transferred from net proceeds		$ 220,800,000
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] | 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] | 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] | 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
Line of credit			$ 27,000,000
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] | 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] | 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