Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Effective Income Tax Rate, Percent	21.10%	32.80%	13.00%	30.80%
Valuation Allowance [Abstract]
Valuation Allowance, Amount	$ 0		$ 0		$ 0
Income Tax Uncertainties [Abstract]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	3,100		3,100		4,800
Unrecognized Tax Benefits, Period Increase (Decrease)	(700)	$ (1,200)	(1,900)	$ (2,900)
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	900		900		$ 2,300
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	(600)	$ (500)	(1,400)	$ (1,300)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance beginning of period			5,839
Additions based on tax positions related to current year			56
Additions for tax positions of prior years			0
Reductions for tax positions of prior years			0
Reductions due to lapse of applicable statute of limitations			(1,954)
Settlements			0
Balance end of period	3,941		3,941
Maximum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	1,000		1,000
Minimum [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound	$ (500)		$ (500)