Commitments and Contingent Liabilities - Additional Information (Details)	1 Months Ended	12 Months Ended
	May. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Loss Contingencies [Line Items]
Rental expense		$ 17,800,000	$ 19,700,000	$ 16,000,000
Compensation guarantees payable		$ 0	$ 0
Revolving Credit Facility
Loss Contingencies [Line Items]
Weighted average interest rate		4.44%
Debt term		3 years
Guarantee Obligations
Loss Contingencies [Line Items]
Letters of credit obligation		$ 11,600,000
Indemnification Agreement
Loss Contingencies [Line Items]
Number of loans with contingent potential obligation | loan		40
Maximum potential losses on loans		$ 8,500,000.0
Payment of indemnification		$ 500,000
KCGA | Settled Litigation | Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Settlement expense, fine	$ 300,000
Litigation settlement, amount	686,000
Settlement interest	$ 70,000