Income Taxes (Income Tax Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income before provision for income taxes	$ 134,715	$ 133,828	$ 79,559
Federal income tax expense at statutory rate	28,289	28,104	16,707
Increases (decreases) resulting from:
State income taxes, net of federal income tax benefits	10,236	6,430	6,060
Non-deductible expenses	2,982	1,385	1,993
Impact of Tax Cuts and Jobs Act of 2017	0	0	(2,691)
Excess tax benefits on stock-based compensation	(206)	(1,488)	(778)
Other	916	907	108
Loss carryforwards from tax consolidation of subsidiary	(5,622)	0	0
Changes in valuation allowance, net of equity and tax audit adjustments	5,182	(2,525)	153
Income tax expense	$ 41,777	$ 32,813	$ 21,552