Stockholders' Equity (Additional Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Class of Stock [Line Items]
Gross proceeds from issuance of common stock		$ 212,900
Net proceeds from issuance of stock		211,774
Aggregate value of units redeemed		$ 0
Preferred stock, shares outstanding	1,716,837		1,716,837
Preferred stock, par value (in usd per share)	$ 1		$ 1
Percentage of restriction on ownership (more than)	3.90%
Common Stock
Class of Stock [Line Items]
Number of shares issued during period		6,300,000
Stock issuance costs		$ 1,100
Net proceeds from issuance of stock		$ 211,800
Number of units redeemed in exchange for common stock (in shares)		300,821
Aggregate value of units redeemed		$ 10,100
TIER | Common Stock
Class of Stock [Line Items]
Number of shares issued in merger	41,600,000