Basis of Presentation and Significant Accounting Policies - Summary of Table Reconciling Basic and Diluted Net Income Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income	$ 33,456	$ 34,709	$ 39,122	$ 26,977	$ 31,985	$ 37,669	$ 26,156	$ 20,906	$ 134,264	$ 116,716	$ 103,667
Basic Earnings Per Share, Weighted average common shares outstanding									127,705	115,726	107,818
Basic Earnings Per Share	$ 0.25	$ 0.25	$ 0.31	$ 0.24	$ 0.28	$ 0.33	$ 0.22	$ 0.18	$ 1.05	$ 1.01	$ 0.96
Net income	$ 33,456	$ 34,709	$ 39,122	$ 26,977	$ 31,985	$ 37,669	$ 26,156	$ 20,906	$ 134,264	$ 116,716	$ 103,667
Diluted Earnings Per Share, Weighted average common shares outstanding									127,705	115,726	107,818
Effect of dilutive securities: Restricted stock									543	440	488
Effect of dilutive securities: Stock options									53	89	59
Diluted Earnings Per Share, Weighted average shares outstanding	135,383	135,011	127,973	114,563	114,716	115,153	116,223	119,076	128,301	116,255	108,365
Diluted Earnings Per Share	$ 0.25	$ 0.25	$ 0.31	$ 0.24	$ 0.27	$ 0.33	$ 0.22	$ 0.18	$ 1.05	$ 1.00	$ 0.95