Income Taxes Current Deferred Income Tax (Details) (Tables) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Current Federal Tax Expense (Benefit)	$ 10,243	$ 10,321	$ 10,822
Current State and Local Tax Expense (Benefit)	3,030	3,375	3,386
Current Income Tax Expense (Benefit)	13,273	13,696	14,208
Deferred Federal Income Tax Expense (Benefit)	2,341	(506)	(1,522)
Deferred State and Local Income Tax Expense (Benefit)	(224)	(166)	(153)
Deferred Income Tax Expense (Benefit)	(1,073)	(918)	(1,675)
Provision for income taxes	15,390	13,024	12,533
Federal and State [Member]
Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]
Deferred Income Tax Expense (Benefit)	$ 2,117	$ (672)	$ (1,675)