Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended	12 Months Ended
	Feb. 15, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock repurchased during period		$ (14,483)	$ (24,779)	$ (377)
Preferred Stock [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, shares authorized (in shares)		500,000
Preferred stock, par value (in dollars per share)		$ 20
Preferred stock, shares outstanding (in shares)		0	0
Series A Preferred Stock [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Preferred stock, shares authorized (in shares)		30,000
Preferred stock, voting rights		Each share of the Series A Preferred Stock shall entitle the holder to one thousand votes
Stock Repurchase Program 2015 [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock repurchase program, authorized amount					$ 20,000
Stock repurchased during period (in shares)				(10,135)	(551,791)
Stock repurchased during period				$ (400)	$ (19,600)
Stock Repurchase Program 2017 [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock repurchase program, authorized amount			$ 30,000
Stock repurchased during period (in shares)		(112,307)	(539,760)
Stock repurchased during period		$ (5,200)	$ (24,800)
Stock Repurchase Program 2018 [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock repurchase program, authorized amount		$ 20,000
Stock repurchased during period (in shares)		(201,484)
Stock repurchased during period		$ (9,300)
Stock repurchase program, remaining authorized amount		$ 10,700
Stock Repurchase Program 2018 [Member] | Subsequent Event [Member]
Preferred Stock, Number of Shares, Par Value and Other Disclosures [Abstract]
Stock repurchased during period (in shares)	0