Equity-Based Compensation (Details)							1 Months Ended	3 Months Ended									12 Months Ended
	Jun. 24, 2015 USD ($) $ / shares shares	Mar. 11, 2015 $ / shares shares	May. 20, 2014 USD ($) shares	Nov. 24, 2013	Oct. 13, 2013 $ / shares shares	Oct. 07, 2013 USD ($) $ / shares shares	Oct. 31, 2013	Dec. 31, 2015 USD ($) shares	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2013 USD ($) $ / shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) $ / shares	Dec. 31, 2012 shares
Estimated value of withheld shares																	$ 327,000	$ 1,781,000
Income tax benefit realized upon issuance of underlying shares																	2,770,000	736,000
Equity-based compensation expense																	1,453,000	2,002,000	$ 2,995,000
Tax Benefit related to the restricted stock units granted								$ 3,148,000	$ 3,277,000	$ 3,457,000	$ 2,148,000	$ 1,818,000	$ 3,116,000	$ 3,129,000	$ 1,885,000	$ 1,071,000	$ 12,030,000	$ 9,948,000	2,844,000
Stock split																	0.25
Options outstanding, remaining contractual term																	6 years 10 months 24 days
Options to acquire shares granted | shares								28,057				652,500					28,057	652,500
Exercise of stock options, Value																	$ 2,248,000	$ 486,000	$ 0
Corporate income tax benefit																	2,716,000	519,000
Total intrinsic value of stock options exercised																	$ 19,154,000	$ 3,839,000
RMCO, LLC
Stock split							25
Options outstanding, Exercise price | $ / shares																$ 3.60			$ 3.60
Options outstanding, remaining contractual term																			8 years 10 months 24 days
2013 Stock Incentive Plan
Additional shares available to grant under plan (in shares) | shares								1,936,215									1,936,215
Class A common stock
Restricted stock units granted (in shares) | shares	2,941
Restricted stock units granted, value per unit (in dollars per share) | $ / shares	$ 34.01
Shares withheld from grants to employee | shares	940		30,519
Estimated value of withheld shares	$ 32,000
Options granted | shares																	787,500
Stock split						1
Incremental compensation cost																	$ 0
Weighted average grant-date fair value of common unit options | $ / shares		$ 32.45			$ 22.00
Class A common stock | RMCO, LLC
Stock split				1
Options to acquire shares granted | shares								787,500									787,500
Class A common stock | Former Chief Executive Officer Member
Options outstanding, remaining contractual term																		2 years
Incremental compensation cost																	$ 0
Class B Common Units
Unrecognized compensation cost																$ 0			$ 0
Weighted average grant-date fair value of common unit options | $ / shares																			$ 56.83
Total fair value of options																			$ 895,000
Class B Common Units | Employees | RMCO, LLC
Options granted | shares																				31,500
Options to acquire shares granted | shares						31,500
Class B common stock | RMCO, LLC
Stock split																	0.25
Restricted Stock Units (RSUs)
Restricted stock units granted (in shares) | shares						107,971
Restricted stock units granted, value per unit (in dollars per share) | $ / shares						$ 18.96
Shares withheld from grants to employee | shares			30,519														7,933
Estimated value of withheld shares			$ 818,000														$ 295,000
Income tax benefit realized upon issuance of underlying shares						$ 125,000
Equity-based compensation expense																	1,453,000	$ 2,002,000	247,000
Tax Benefit related to the restricted stock units granted																			345,000
Unrecognized compensation cost								$ 2,141,000									$ 2,141,000
Options, Vested and expected to vest | shares								12,109									12,109
Options outstanding, remaining contractual term																	2 years
Tax Benefit related to the restricted stock units granted																		$ 92,000
Non-cash compensation expense																			2,047,000
Incremental compensation cost																	$ 59,000
Restricted Stock Units (RSUs) | Employees
Restricted stock units granted (in shares) | shares		74,893				115,699
Restricted stock units granted, value per unit (in dollars per share) | $ / shares		$ 32.45				$ 22.00
Vesting Period		3 years				3 years
Tax Benefit related to the restricted stock units granted																	$ 54,000
Restricted Stock Units (RSUs) | Directors
Restricted stock units granted (in shares) | shares		10,787			18,184
Restricted stock units granted, value per unit (in dollars per share) | $ / shares		$ 32.45			$ 22.00
Common unit options | Class B Common Units
Non-cash compensation expense																			$ 701,000