Equity (Details) $ / shares in Units, $ in Thousands		3 Months Ended				12 Months Ended
	Feb. 03, 2020 day $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2020 $ / shares	Jun. 30, 2020 $ / shares	Mar. 31, 2020 $ / shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($) $ / shares	Dec. 31, 2018 USD ($) $ / shares	May 31, 2020 shares
Equity, Class of Treasury Stock [Line Items]
Preferred stock conversion, threshold consecutive trading days | day	20
Cash dividends declared per common share (in dollars per share) | $ / shares		$ 0.82	$ 0.82	$ 0.67	$ 0.67	$ 2.98	$ 2.44	$ 2.00
Dividends | $						$ 25,000
Dividends payable | $		$ 9,013				$ 9,013	$ 8,915
Number of additional shares authorized to be repurchased (in shares)									750,000
Common stock authorized to be repurchased (in shares)		4,930,045				4,930,045
Shares repurchased during period (in shares)						279,796
Weighted average price (in dollars per share) | $ / shares						$ 116.13
Total cost of shares repurchased | $						$ 32,500	$ 40,000	$ 27,501
Common stock shares available for repurchase (in shares)		722,642				722,642
Convertible preferred stock
Equity, Class of Treasury Stock [Line Items]
Preferred stock, shares issuable upon conversion (in shares)	1,150,000
Conversion ratio	0.7938
Conversion price of stock (in dollars per share) | $ / shares	$ 125.97
Common Stock
Equity, Class of Treasury Stock [Line Items]
Shares issued during period, conversion of convertible preferred stock (in shares)	912,870