Common Stock and Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands					1 Months Ended	133 Months Ended
	Apr. 03, 2020	Mar. 12, 2020	Oct. 15, 2019	Apr. 15, 2019	Apr. 30, 2009	May 05, 2020
Common Stock and Dividends
Cash dividends paid to common shareholders (in dollars per share)	$ 0.55		$ 0.55	$ 0.50
Repurchase of common stock, authorized amount		$ 50,000			$ 40,000
Period of repurchase of common stock		12 months			12 months
Cumulative number of shares repurchased under all stock repurchase programs						12,261,282
Cumulative cost of shares repurchased under all stock repurchase programs						$ 356,883