Stockholders' Equity - Stock Compensation - Nonvested - Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted Stock Awards
Shares
Outstanding, beginning of period (in shares)	39,761	11,795	31,102
Awarded (in shares)	54,314	41,905	11,795
Vested (in shares)	(39,761)	(13,939)	(31,102)
Outstanding, end of period (in shares)	54,314	39,761	11,795
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share)	$ 65.40	$ 89.05	$ 68.00
Awarded (in dollars per share)	76.72	65.60	89.05
Vested (in dollars per share)	65.40	85.99	68.00
Outstanding, end of period (in dollars per share)	$ 76.72	$ 65.40	$ 89.05
Restricted Stock Units (RSUs)
Shares
Outstanding, beginning of period (in shares)	256,430	156,750	163,289
Awarded (in shares)	355,689	212,065	111,033
Vested (in shares)	(108,996)	(68,993)	(84,627)
Forfeited (in shares)	(74,761)	(43,392)	(32,945)
Outstanding, end of period (in shares)	428,362	256,430	156,750
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share)	$ 74.12	$ 86.68	$ 66.46
Awarded (in dollars per share)	62.48	67.92	99.29
Vested (in dollars per share)	75.15	81.95	65.20
Forfeited (in dollars per share)	64.79	76.71	84.17
Outstanding, end of period (in dollars per share)	$ 65.83	$ 74.12	$ 86.68
Performance Based Restricted Stock Units ("PSUs")
Shares
Outstanding, beginning of period (in shares)	248,559	209,019	202,315
Awarded (in shares)	138,114	101,498	80,502
Vested (in shares)	(52,861)	(43,109)	(33,592)
Forfeited (in shares)	(54,867)	(18,849)	(40,206)
Outstanding, end of period (in shares)	278,945	248,559	209,019
Weighted Average Grant Date Fair Value
Outstanding, beginning of period (in dollars per share)	$ 104.27	$ 103.38	$ 84.63
Awarded (in dollars per share)	76.88	101.82	141.61
Vested (in dollars per share)	76.24	97.12	85.0
Forfeited (in dollars per share)	85.09	97.49	100.96
Outstanding, end of period (in dollars per share)	$ 99.80	$ 104.27	$ 103.38