Stockholders' Equity - Cash Dividends Declared - Common Stock (Details) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Stockholders' Equity Note [Abstract]
Cash dividend per share (in dollars per share)	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20	$ 0.20