Capital Stock - Common Stock (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Feb. 28, 2022	Feb. 28, 2021
Class of Stock [Line Items]
Stock repurchase program, authorized amount				$ 250,000,000
Stock repurchased during period (in shares)	0	161,000
Stock repurchased during period, average price (in dollars per share)		$ 11.39
Stock repurchased during period	$ 0	$ 1,828,000
Remaining authorized repurchase amount	226,000,000
Common dividends declared	$ 78,601,000	$ 69,986,000
Dividends declared per share of common stock (usd per share)	$ 0.33	$ 0.30
Sales Agreements
Class of Stock [Line Items]
Aggregate offering price			$ 500,000,000
Regular Dividend
Class of Stock [Line Items]
Common dividends declared	$ 79,000,000	$ 70,000,000