Compensation Plans - Changes in OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	$ 603,804	$ 548,573	$ 387,098
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(2,077)	(4,630)	27,031
Reclassification for the adoption of ASU 2016-09		(834)
Debt Securities, Held-to-maturity, Transfer, Derivative Hedge, Gain (Loss)	0
Balance	867,185	603,804	548,573
Accumulated other comprehensive income (loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(9,282)	(3,818)	(1,741)
Balance	17,749	(9,282)	(3,818)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(9,047)	(3,622)	(1,533)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(2,089)	(4,633)	29,226
Reclassification for the adoption of ASU 2016-09		(792)
Debt Securities, Held-to-maturity, Transfer, Derivative Hedge, Gain (Loss)	(5,202)
Balance	14,977	(9,047)	(3,622)
AOCI, Accumulated Gain (Loss), Held To Maturity Securities [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	(235)	(196)	(208)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	12	3	(33)
Reclassification for the adoption of ASU 2016-09		(42)
Debt Securities, Held-to-maturity, Transfer, Derivative Hedge, Gain (Loss)	5,202
Balance	4,934	(235)	(196)
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance	0	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	0	0	(2,162)
Reclassification for the adoption of ASU 2016-09		0
Debt Securities, Held-to-maturity, Transfer, Derivative Hedge, Gain (Loss)	0
Balance	$ (2,162)	$ 0	$ 0