Shareholders' Equity - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019	Nov. 12, 2019
Class of Stock [Line Items]
Cash dividends received	$ 12,694	$ 10,236	$ 39,448	$ 18,350
Repurchase of common stock (in shares)						1,525,000
Shares repurchased as a percentage of total shares outstanding						5.00%
Repurchase of common stock	$ 8,009	$ 3,660	25,304	4,695
Market value of shares repurchased under equity compensation plans			$ 494	$ 4,695
Minimum
Class of Stock [Line Items]
Company's common stock in lieu of cash to exercise options to purchase shares (in shares)	11,306		11,439
Maximum
Class of Stock [Line Items]
Company's common stock in lieu of cash to exercise options to purchase shares (in shares)		15,151		15,242
2007 Stock Repurchase Plan
Class of Stock [Line Items]
Stock repurchase program cumulative number of shares repurchased during the period (in shares)					0
2019 Stock Repurchase Plan
Class of Stock [Line Items]
Cumulative number of shares repurchased (in shares)					0
Repurchase of common stock (in shares)	259,993		813,862
Repurchase of common stock	$ 7,669		$ 24,809
Common Stock
Class of Stock [Line Items]
Repurchase of common stock (in shares)	271,299	93,755	829,969	119,914
Repurchase of common stock	$ 4,833	$ 1,672	$ 14,795	$ 2,138
Common Stock | Minimum
Class of Stock [Line Items]
Company's common stock in lieu of cash to exercise options to purchase shares (in shares)	0		4,668
Market value of shares repurchased under equity compensation plans	$ 346		$ 494
Common Stock | Maximum
Class of Stock [Line Items]
Company's common stock in lieu of cash to exercise options to purchase shares (in shares)		93,755		119,914
Market value of shares repurchased under equity compensation plans		$ 3,659		$ 4,695