Fair Value Measurements (Aggregate Fair Value, Contractual Balance, and Gain or Loss for Loans Held-For-Sale) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Aggregate fair value	$ 85,030	$ 52,133
Contractual balance	82,080	50,597
Unrealized gain	$ 2,950	$ 1,536