Derivative Financial Instruments - Changes in Net Gain or Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Loss (Details) - Interest rate swap agreements - Cash flow hedges - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Changes in Net Gain or Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Loss
Balance at the beginning of the period	$ (2,936)	$ 0
Unrealized loss recognized in other comprehensive loss, net of tax	(8,806)	(4,838)
Reclassification to interest expense, net of tax	1,605	1,902
Balance at the end of the period	$ (10,137)	$ (2,936)

Derivative Financial Instruments - Changes in Net Gain or Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Loss (Details) - Interest rate swap agreements - Cash flow hedges - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2019

Dec. 31, 2018

Changes in Net Gain or Loss on Cash Flow Hedges Included in Accumulated Other Comprehensive Loss

Balance at the beginning of the period

$ (2,936)

$ 0

Unrealized loss recognized in other comprehensive loss, net of tax

(8,806)

(4,838)

Reclassification to interest expense, net of tax

1,605

1,902

Balance at the end of the period

$ (10,137)

$ (2,936)