Income Taxes (Narrative) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Federal NOL carryforward limiit due to IRC 382		$ 4,800
Current income tax expense (benefit)		35,910	$ 22,084	$ 17,837
Income tax expense		37,176	24,402	14,266
State net operating loss carryforwards		75,100
Share based compensation related tax expense		300	1,900
Windfall Tax Benefits				400
Stock-based compensation		3,399	2,388
Income taxes payable		902	0
Current taxes payable		21,028	20,741
Income taxes receivable		0	3,748
Income taxes paid		34,200	23,500
Income tax refunds received		2,900	600
Valuation allowance		145	145	125	$ 126
Reduction of tax indemnification asset		$ 10,646	$ 5,690	$ 4,070
Income tax expense at statutory rate	21.00%	21.00%	35.00%	35.00%
Deferred Tax Benefit, 2017 Tax Act		$ 500	$ 3,600
Net deferred tax (liability) asset		$ 3,034	$ 1,768
Effective tax rate		23.70%	29.80%	31.60%
Income from continuing operations before income taxes		$ 156,914	$ 81,827	$ 45,146
State and Local Jurisdiction [Member]
Income Tax Contingency [Line Items]
Income tax examination period		3 years
Federal [Member]
Income Tax Contingency [Line Items]
Income tax examination period		3 years
Tax Year 2028 [Member]
Income Tax Contingency [Line Items]
NOL expiration		$ 29,400
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
Tax Year 2008 [Member]
Income Tax Contingency [Line Items]
Period under examination		Jul. 31, 2008
Tax Year 2008 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Open tax year end		Jul. 31, 2008
Tax Year 2009 [Member]
Income Tax Contingency [Line Items]
Period under examination		May 05, 2009
Tax Year 2009 [Member] | Federal [Member]
Income Tax Contingency [Line Items]
Open tax year end		May 05, 2009
IRC 382 [Member]
Income Tax Contingency [Line Items]
Tax Expense Benefit, Net Operating Loss Carry Forward				$ (1,700)