Loans Receivable and Allowance for Credit Losses (Summary of Activities in Allowance for Unfunded Credit Reserves) (Details) - Allowance for Unfunded Credit Reserves - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Allowance for unfunded credit reserves
Allowance for unfunded credit reserves, beginning of period	$ 13,614	$ 15,174	$ 13,318	$ 16,121
Provision for (reversal of) unfunded credit reserves	405	14	701	(933)
Allowance for unfunded credit reserves, end of period	$ 14,019	$ 15,188	$ 14,019	$ 15,188