Stockholders' Equity - Computation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 25,031	$ 73,795	$ 61,366	$ 48,545	$ 43,301	$ 42,710	$ 47,218	$ 42,402	$ 208,737	$ 175,631	$ 144,738
Denominator:
Basic weighted average shares outstanding	115,360,256	115,344,015	115,362,757	115,663,366	115,791,757	115,773,030	115,733,934	116,259,058	115,461,016	115,888,859	116,861,194
Effect of dilutive securities:
Diluted weighted average shares outstanding	115,631,911	115,625,760	115,662,626	116,017,400	116,169,754	116,134,623	116,061,988	116,647,442	115,762,843	116,252,866	117,315,498
Basic earnings per share	$ 0.22	$ 0.64	$ 0.53	$ 0.42	$ 0.37	$ 0.37	$ 0.41	$ 0.37	$ 1.81	$ 1.52	$ 1.24
Diluted earnings per share	$ 0.21	$ 0.64	$ 0.53	$ 0.42	$ 0.37	$ 0.37	$ 0.41	$ 0.37	$ 1.80	$ 1.51	$ 1.24
Stock appreciation rights [Member]
Effect of dilutive securities:
Dilutive securities									180,875	192,579	248,850
Restricted stock [Member]
Effect of dilutive securities:
Dilutive securities									120,952	171,428	205,454