Reconciliation of Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income from continuing operations for basic and diluted earnings per share	$ 26,105	$ 25,764	$ 79,216	$ 53,987
Net income from discontinued operations for basic and diluted earnings per share		88,846		98,842
Net income	$ 26,105	$ 114,610	$ 79,216	$ 152,829
Weighted average shares outstanding - basic	33,034	33,399	33,385	33,387
Dilutive effect of stock options and restricted stock	231	206	137	161
Weighted average shares outstanding - diluted	33,265	33,605	33,522	33,548
Earnings per share from continuing operations
Basic	$ 0.79	$ 0.77	$ 2.37	$ 1.62
Diluted	0.78	0.77	2.36	1.61
Earnings per share from discontinued operations
Basic		2.66		2.96
Diluted		2.64		2.95
Earnings per share net income
Basic	0.79	3.43	2.37	4.58
Diluted	$ 0.78	$ 3.41	$ 2.36	$ 4.56