Employee Benefit Plans (Employee Stock Purchase Plan) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Percentage of quoted market price on the last day of each calendar quarter at which employee stock purchase plan allows participants to purchase the Company's common stock	95.00%
Stock issuances under stock purchase plan (in shares)	117,153	113,941	130,085
Reserve for stock issuance (in shares)	2,900,000
Total employee contributions	$ 1.9