Stock-Based Compensation and Stock Repurchases (Narrative) (Details) - USD ($)	1 Months Ended		12 Months Ended						36 Months Ended
	Apr. 30, 2016	Mar. 31, 2016	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2016	Sep. 30, 2016	May 16, 2014	Dec. 31, 2013
Equity And Stock-Based Compensation [Line Items]
Restricted vesting period			5 years
Unrecognized estimated compensation cost related to non-vested stock options granted			$ 554,000						$ 554,000
Recognition period of unrecognized compensation cost			1 year 11 months 12 days
Intrinsic unrealized value of all options outstanding, vested and expected to vest			$ 2,584,500,000		$ 1,401,321,000		$ 2,476,230,000		2,584,500,000
Cash received from exercise of stock options			142,000,000,000		3,000,000		978,000
Total Paid			$ 2,850,000	[1]	$ 3,110,000	[1]	$ 4,070,000	[1]	$ 10,030,000
Share price			$ 15.68		$ 12.95		$ 9.42		$ 11.74
Stock Option [Member]
Equity And Stock-Based Compensation [Line Items]
Compensation expense			$ 284,000		$ 282,000		$ 146,000
Restricted Stock Units (RSUs) [Member]
Equity And Stock-Based Compensation [Line Items]
Compensation expense			419,000
Unrecognized estimated compensation cost related to non-vested stock options granted			$ 396,000						$ 396,000
Common Stock shares remaining for future issuances										68,153
Restricted Stock Units (RSUs) [Member] | Employee/Director [Member]
Equity And Stock-Based Compensation [Line Items]
Options granted	5,625	62,528
Restricted Stock Units (RSUs) [Member] | Executive Officer [Member]
Equity And Stock-Based Compensation [Line Items]
Vesting period of stock options and RSU			4 years
Percentage of shares vested			25.00%
Restricted Stock Units (RSUs) [Member] | Director [Member]
Equity And Stock-Based Compensation [Line Items]
Vesting period of stock options and RSU			1 year
Percentage of shares vested			100.00%
May 2014 Stock Repurchase Plan [Member]
Equity And Stock-Based Compensation [Line Items]
Repurchase program, amount authorized											$ 10,000,000
Repurchase program, shares authorized											350,000
Class A Nonvoting Common Stock [Member]
Equity And Stock-Based Compensation [Line Items]
Common Stock authorized for issuance under 2010 Stock Incentive Plan			1,250,000						1,250,000
Common Stock shares remaining for future issuances			604,857						604,857
Class A [Member]
Equity And Stock-Based Compensation [Line Items]
Options exercised			46,815		185,685		157,600
Options granted			169,327		112,000		80,000
Options outstanding			535,077		486,565		568,250		535,077			709,850
Class A [Member] | James Cotter Jr. [Member]
Equity And Stock-Based Compensation [Line Items]
Stock options terminated			50,000
Minimum [Member]
Equity And Stock-Based Compensation [Line Items]
Vesting period of stock options and RSU			0 years
Maximum [Member]
Equity And Stock-Based Compensation [Line Items]
Vesting period of stock options and RSU			4 years

[1] Certain 2015 and 2014 balances included the restatement impact as a result of a change in accounting principle (see Note 2 - Summary of Significant Accounting Policies - Accounting Changes).