Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 73,045	$ 14,254	$ 3,413
Goodwill, Acquired During Period	59,475	10,841
Goodwill, Other Increase (Decrease)	(684)
Goodwill, Impairment Loss	0	$ 0
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	13,920
Finite-Lived Intangible Assets, Amortization Expense, Year Two	5,355
Finite-Lived Intangible Assets, Amortization Expense, Year Three	4,267
Finite-Lived Intangible Assets, Amortization Expense, Year Four	3,555
Finite-Lived Intangible Assets, Amortization Expense, Year Five	$ 3,246