Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Allowance for credit losses	$ 2,504	$ 2,427
Amounts pledged	752,758	518,123
Accumulated amortization	53,241	42,211
Accumulated allowance	8,555	8,606
Net accumulated depreciation	102,640	103,547
Deferred tax assets, gross	$ 63,130	$ 68,622
Class A Stock [Member]
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	13,333,368	13,530,688
Common stock, shares outstanding (in shares)	13,333,368	13,530,688
Common stock, par value (dollars per share)	$ 0.001	$ 0.001
Class B Stock [Member]
Common stock, shares authorized (in shares)	99,680	99,680
Common stock, shares issued (in shares)	99,680	99,680
Common stock, shares outstanding (in shares)	99,680	99,680
Common stock, par value (dollars per share)	$ 0.001	$ 0.001