Schedule I - Condensed Balance Sheets (Parenthetical) (Detail) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, shares authorized		100,000,000	100,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		1,000,000,000	1,000,000,000
Common stock, shares issued		92,637,403	91,861,054
Treasury stock, shares		6,519,773	6,519,773
Accumulated other comprehensive loss		$ (5,076)	$ (13,694)
Parent Company [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Preferred stock, par value		$ 0.01	$ 0.01
Preferred stock, shares authorized		100,000,000	100,000,000
Preferred stock, shares issued		0	0
Preferred stock, shares outstanding		0	0
Common stock, par value		$ 0.01	$ 0.01
Common stock, shares authorized		1,000,000,000	1,000,000,000
Common stock, shares issued		92,637,403	91,861,054
Treasury stock, shares		6,519,773	6,519,773
Accumulated other comprehensive loss	[1]	$ (5,076)	$ (13,694)
The impact of an immaterial correction of an error		The parent company only condensed statements of comprehensive (loss) income reflect a correction to record its wholly owned subsidiary’s other comprehensive income (loss), which had previously been omitted for 2016 and 2015. The correction of this immaterial omission did not impact the Company’s consolidated financial statements for any periods presented.
Parent Company [Member] | Immaterial Error Correction [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Accumulated other comprehensive loss			$ (13,694)
The impact of an immaterial correction of an error		The 2016 parent company only condensed balance sheet reflects a correction to record accumulated other comprehensive loss which had previously been omitted. The correction of this immaterial omission reduced the previously reported investment in wholly owned subsidiary and total stockholders’ equity at December 31, 2016 by $13,694. The correction did not impact the Company’s consolidated financial statements for any periods presented.

[1] The 2016 parent company only condensed balance sheet reflects a correction to record accumulated other comprehensive loss which had previously been omitted. The correction of this immaterial omission reduced the previously reported investment in wholly owned subsidiary and total stockholders’ equity at December 31, 2016 by $13,694. The correction did not impact the Company’s consolidated financial statements for any periods presented.