Stockholders' Equity - Summary of Activity in Stockholders' Equity (Parenthetical) (Detail) - $ / shares	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Capitalization, Equity [Line Items]
Cash dividends declared on common stock, per share	$ 0.275		$ 0.275		$ 0.55	$ 0.55
Repurchase of restricted common stock, shares		14,272
Retained Earnings [Member]
Schedule of Capitalization, Equity [Line Items]
Cash dividends declared on common stock, per share	$ 0.275	$ 0.275	$ 0.275	$ 0.275