Long-Term Debt - Effects of Interest Rate Swap and Cap Agreements (Details) - Cash Flow Hedging - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Amount of unrealized gains (losses) in OCI on interest rate cap and swap agreements	$ 1,151	$ (133)	$ (5,437)
Reclassification from accumulated other comprehensive income into net income	6,377	6,286	5,058
Tax benefit (expense)
Derivative Instruments, Gain (Loss) [Line Items]
Amount of unrealized gains (losses) in OCI on interest rate cap and swap agreements	(415)	48	3,460
Reclassification from accumulated other comprehensive income into net income	(2,214)	(2,180)	(3,220)
Interest rate cap agreements | Debt Expense
Derivative Instruments, Gain (Loss) [Line Items]
Amount of unrealized gains (losses) in OCI on interest rate cap and swap agreements	1,566	(181)	(8,897)
Reclassification from accumulated other comprehensive income into net income	$ 8,591	$ 8,466	$ 8,278