Goodwill And Intangible Assets (Schedule Of Acquired Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 254,454	$ 145,355
Accumulated amortization	77,965	62,739
Net	176,489	82,616
Client Contracts And Broker Relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	232,560	124,261
Accumulated amortization	60,569	47,013
Net	171,991	77,248
Trade Names
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	3,880	3,880
Accumulated amortization	3,078	2,405
Net	802	1,475
Technology
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	14,646	13,846
Accumulated amortization	11,867	11,039
Net	2,779	2,807
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	2,232	2,232
Accumulated amortization	1,941	1,870
Net	291	362
Favorable Lease
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,136	1,136
Accumulated amortization	510	412
Net	$ 626	$ 724