Capital Structure - Purchase of Common Stock from Employees Withholding Tax Payments Related to Vesting of Restricted Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Equity [Abstract]
Shares repurchased (in shares)	0	0	26,601	22,666
Total consideration	$ 0	$ 0	$ 2,012	$ 1,408
Weighted average purchase price per share (in dollars per share)	$ 0	$ 0	$ 75.63	$ 62.11