Litigation, Commitments, and Contingencies - Litigation (Detail) $ in Millions				1 Months Ended		12 Months Ended
	Jan. 31, 2014 USD ($)	Apr. 30, 2013 item	Feb. 17, 2010 USD ($) claim	Jul. 31, 2013 USD ($) claim	Nov. 30, 2011 item	Dec. 31, 2015 USD ($)
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount awarded by jury to Capital Funding	$ 1.8
Unjust enrichment judgment amount	$ 10.4
Capital Funding Litigation
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Number of claims asserted against all defendants | claim			3
Maximum liability						$ 3.0
Counts of breach of contract filed for summary judgment by defendants | item					2
Counts of promissory estoppel filed for summary judgment by defendants | item					2
Counts of unjust enrichment filed for summary judgment by defendants | item					2
Counts of unfair competition filed for summary judgment by defendants | item					2
Counts of unjust enrichment for which Court issued Opinion and Order which granted the motion | item		1
Period of jury trial				14 days
Number of claims not dismissed | claim				2
Capital Funding Litigation | Minimum
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount of damages sought by plaintiff			$ 30.0
Amount agreed to be paid by William Walker and Mallory Walker to Column						3.0
Capital Funding Litigation | Maximum
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount up to which the entity will be indemnifying Column						3.0
Amount agreed to be paid by William Walker and Mallory Walker to Column						6.0
Capital Funding Litigation | All Defendants
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount awarded by jury to Capital Funding				$ 1.8
Capital Funding Litigation | Credit Suisse
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount awarded by jury to Capital Funding				$ 10.4
CA Funds Group Litigation
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Amount of damages sought by plaintiff						5.1
Amount raised in separate account						380.0
CA Funds Group Litigation | Maximum
LITIGATION, COMMITMENTS, AND CONTINGENCIES
Floating rate loan amount						$ 25.0
Minimum floating rate loan period under bridge program						3 years