Stockholders' Equity - Treasury Stock (Details) - USD ($)	3 Months Ended			9 Months Ended	12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Shares purchased during period (shares)	401,342	0	131,012	532,354
Average price paid per share (usd per share)	$ 11.83	$ 0.00	$ 13.77	$ 12.31
Commissions paid to acquire shares				$ 21,294
Common Stock Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Shares purchased during period (shares)	401,342	0	131,012	532,354
Treasury stock acquired during period	$ 0	$ 4,749,000	$ 4,749,000		$ 6,555,000