Stockholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Nov. 30, 2014
Class of Stock [Line Items]
Common stock, shares authorized		90,000,000.0	90,000,000
Common stock, par value (usd per share)		$ 1	$ 1
Common stock, shares issued		66,900,000	66,400,000
Common stock, shares outstanding		60,500,000	60,200,000
Preference stock, shares authorized		800,000
Preference stock, par value (usd per share)		$ 1
Cash dividends declared per common share (usd per share)		$ 0.32	$ 0.31	$ 0.28
Shares acquired		48,409	62,500	0
Purchases of treasury stock		$ 1,000,000.0	$ 1,200,000	$ 0
Cash dividends paid to stockholders		$ 19,300,000	$ 18,700,000	$ 16,800,000
Subsequent Event
Class of Stock [Line Items]
Cash dividends declared per common share (usd per share)	$ 0.08
November 2014 Repurchase Program
Class of Stock [Line Items]
Share repurchase program, authorized amount					$ 75,000,000.0