Income Taxes (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2018	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Contingency [Line Items]
Federal NOL carryforward limiit due to IRC 382			$ 4,800
Current income tax expense (benefit)			24,478	$ 35,910	$ 22,084
Income tax expense			36,639	37,176	24,402
State net operating loss carryforwards			53,000
Share based compensation related tax expense			200	300	1,900
Stock-based compensation			4,183	3,399
Income taxes payable			0	902
Current taxes payable			19,661	21,028
Income taxes receivable			7,504	0
Income taxes paid			33,700	34,200	23,500
Income tax refunds received			800	2,900	600
Valuation allowance			145	145	145	$ 125
Reduction of tax indemnification asset			$ 13,578	$ 10,646	$ 5,690
Income tax expense at statutory rate	21.00%		21.00%	21.00%	35.00%
Deferred Tax Benefit, 2017 Tax Act				$ 500	$ 3,600
Net deferred tax (liability) asset			$ 15,195	$ 3,034
Effective tax rate			25.00%	23.70%	29.80%
Income from continuing operations before income taxes			$ 146,484	$ 156,914	$ 81,827
Tax Year 2028 [Member]
Income Tax Contingency [Line Items]
NOL expiration			24,500
Tax Year 2029 [Member]
Income Tax Contingency [Line Items]
NOL expiration			17,300
Tax Years 2030 through 2034 [Member]
Income Tax Contingency [Line Items]
NOL expiration			31,200
Excess Windfall Tax Benefits [Member] | Income Tax Expense [Member]
Income Tax Contingency [Line Items]
Prior period misstatement		$ 1,500	$ 1,500